View source for The Mind Flayer

{{Update|Info from ''[[Stranger Things VR]]'' needs to be added.|size=140|width=72}}{{TransDividerCustom|10}}
{{Play spoiler}}{{Other|the entity|episode, see [[The Mind Flayer (episode)|"The Mind Flayer"]]. For this entity's proxy incarnations, see [[The Spider Monster]] or [[Hospital Monster]].}}
{{Mind Flayer infobox}}
The '''Shadow Monster''', the '''particles''', and the '''Mind Flayer''' were all names used to describe a '''shadowy entity''' originating from an unknown alternate dimension. The entity's main form consisted of innumerable '''silver-black particles''' linked together through a group intelligence.

The entity was gigantic, looming at least fifty stories tall<ref name=":0" /> and sporting a distinctive spider-like appearance. The Mind Flayer exercised supreme control over {{UD}} via a psychic link, with [[Demogorgon (species)|Demogorgons]], [[vines]], and [[Demobat (species)|Demobats]] forming a shared [[hive mind]]; for a period in {{year|1985}}, possessed humans known as [[the Flayed|"the Flayed"]] also comprised part of the hive mind. This meant the entirety of the Upside Down was essentially like one gigantic organism, with all its contents and agents mentally connected via the Mind Flayer. 

The entity’s first known encounter with humanity occurred in {{year|1950s|the 1950s}}, when a young child named [[Vecna|Henry Creel]] was accidentally transported to [[Dimension X]] and exposed to the entity’s influence; upon returning home, Henry found he had gained special psychokinetic abilities, but was also vulnerable to the entity’s influence, making him use his powers to commit violent acts. Years later, in {{year|1979}}, Creel once again found himself in Dimension X and encountered the shadowy entity once more, though he appeared to have no memory of the earlier event. This time, Henry used his powers to reconstitute the mist into a form that satisfied him: a giant, spider-like entity with a flame-shaped head.<ref name="x">https://www.michaelmaherjr.com/dimension-x</ref><ref name = "S04E09teleplay" />

In {{year|1983}}, a gate to {{UD}} - a dimension somehow related to Dimension X - was accidentally opened by [[Eleven]] at [[Hawkins National Laboratory|Hawkins Lab]]. Henry, also known as Vecna, first actively attempted to take over the world in {{Year|1984}}. Acting through the Mind Flayer - which had since awakened or materialised within the Upside Down - Vecna possessed [[Will Byers]] and an army of adolescent Demogorgons, or "Demodogs". Eleven interfered by closing the gate at Hawkins Lab, severing the psychic link between the worlds and killing the Demodogs in the process. As Eleven closed the Gate, Will's friends and family forced a piece of the Mind Flayer out of his body, which was later rendered dormant after the Gate's closure.

The isolated piece of the Mind Flayer remained dormant at [[Brimborn Steel Works]] until {{year|1985}}, when a newly opened [[Gates|gate]] reestablished the psychic link to Vecna. Via this piece, Vecna began kidnapping and possessing multiple humans and rats, feeding them chemicals and melting their bodies into puddles of biomass. This biomass was then combined to create [[The Spider Monster|a proxy form]], through which Vecna could directly act in the human world; like the Mind Flayer, this proxy form also resembled a spider, and had the same flame-shaped head. However, this proxy form was rendered useless and inert after the new Gate was shut, and the psychic link disabled once again.<ref name = "4ending">''[https://www.youtube.com/watch?v=5Q0iPTc1uSI "Stranger Things 4: Ending Explained"],'' from the ''Netflix Geeked'' YouTube channel.</ref> 

In the same time period, the [[Soviet Union]] somehow captured a portion of the Mind Flayer's particles and stored them at a military base in [[Kamchatka]], along with [[Russian Demogorgon|an adult Demogorgon]] and a number of paralysed Demodogs. [[Jim Hopper|Hopper]], [[Joyce Byers|Joyce]] and [[Murray Bauman|Murray]] escaped the base in March {{year|1986}}, but returned to destroy the Mind Flayer's particles, hoping to aid their allies in Hawkins by inflicting damage to the Upside Down's hive mind. However, upon their return, they discovered that the particles had escaped confinement and possessed the bodies of the paralysed Demogorgons, freeing them. They were forced to change their plans, aiming to kill the Demogorgons instead, as doing so would also destroy fragments of the Mind Flayer, and weaken Vecna in the process.

==History==
{{Spoilers|''[[Stranger Things: The First Shadow|The First Shadow]]''}}
===Background===
The Mind Flayer had unclear origins. According to [[Dustin Henderson|Dustin]], the [[Dungeons & Dragons|''D&D'']] version of the Mind Flayer was "a monster from an unknown dimension", a creature "so ancient that it doesn't even know its true home".{{epref|16}} However, it seems that the entity may have originated from [[Dimension X]], the dimension where the entity was first sighted.

===1940s-1950s===
Following {{year|1943}}'s [[Philadelphia Experiment]] incident, in which the [[USS Eldridge|USS ''Eldridge'']] was accidentally transported to [[Dimension X]], [[Martin Brenner|Dr. Martin Brenner]] and his staff began work on the [[Nevada Experiment|"Nevada Experiment"]], an attempt to reproduce what had happened to the vessel. The government facility that hosted the experiments was located in or around [[Rachel]], [[Nevada]]. However, a rogue staff member defected and stole essential equipment from Brenner, hiding the equipment inside [[Nevada Caves|a nearby cave system]].<ref name="fs">''[[Stranger Things: The First Shadow]]''</ref>

According to one account, it was this equipment which changed the trajectory of [[Henry Creel]]'s life forever. Henry, who was only a small child, was exploring the Nevada caves one day while playing with his spyglass. While exploring, Henry stumbled across the scientific equipment; the technology unexpectedly activated, transporting Henry and the rogue staff member to Dimension X, killing the staff member in the process. In the alternate world, Henry saw glimpses of [[Demogorgon (species)|strange creatures]] and was exposed to the influence of a shadowy entity. Henry survived the ordeal and eventually returned home after 12 hours, but with wildly different blood and an altered personality. 

According to this account, it was Henry’s exposure to the shadowy entity that led him to develop special psychokinetic abilities. This appears to contradict [[The Piggyback|Henry's own account of events]], in which Henry apparently discovered the Mind Flayer and Dimension X at a much later stage in his life.<ref name="fs" /><ref name = "unreliable">In ''SFX Magazine'' #372, the following is said: "While some of Creel's origin story has been told, [[Kate Trefry|[Kate] Trefry]] emphasises that the version of events seen on screen may not be reliable; we were, she notes, told what happened to the Creel family by Henry himself. '[[Stranger Things: The First Shadow|[''The First Shadow''<nowiki>]</nowiki>]] is a different perspective,' she says. 'We're reaching back into Henry's past to understand why he is the way he is.'"</ref>{{epref|34}}
===1959===
Henry Creel and [[Creel family|his family]] later moved to [[Hawkins]], [[Indiana]]. According to Henry, he first discovered he possessed psychokinetic abilities shortly after arriving in [[Creel House|his new home]]. Henry, who held a misanthropic view of humanity, began to psychically torture his family; he forced each family member to experience nightmarish visions. Henry also tested his powers on various animals around the neighbourhood, including rabbits, chickens, squirrels and dogs, torturing and eventually killing them.{{epref|29}}{{epref|32}}

However, according to the alternative account of events, Henry did not consciously choose to kill the animals, but was forced to do so by the shadowy influence. According to this same account, Henry befriended and dated [[Patty Newby]] at this time despite otherwise struggling to make friends upon joining [[Hawkins High School]]. However, throughout their relationship, Henry was haunted by visions of a humanoid monster, and was terrified that he would be made to kill Patty.

Patty convinced Henry to use his powers to track down her biological mother. However, while using the power he called [[The Void|"the battlefield"]], he lost control and frightened Patty. When [[Principal Newby|her father]] walked in and witnessed the scene, he was attacked and almost killed by Henry, being controlled by the shadowy presence. With Patty encouraging Henry to fight back, Henry was able to end the situation, but not before Patty's father was blinded and seriously injured. 

Around this time, [[Martin Brenner|Dr. Martin Brenner]] manipulated Virginia by supplying her with drugs; under the influence of these drugs, Virginia told Brenner everything about her son. After the incident involving Mr. Newby, Virginia agreed to send Henry to see Brenner.

Brenner took Henry to [[Hawkins National Laboratory]]; Brenner explained that he was able to track Henry down due to him dropping his spyglass in the caves, and that Henry had gained a unique blood type due to the incident. Henry, using a sensory deprivation chamber and "the battlefield", showed Brenner [[Demogorgon (species)|a humanoid creature]], displaying the image of the creature via a screen. Later, Brenner tried to force Henry to kill a prisoner, but Henry broke down and ended up stabbing two guards. After this, Henry insisted that he left the laboratory, and Brenner let him go. Upon returning home, Henry sensed that his family was unhappy about his return. Using his powers, he read his mother's thoughts and learned that she wanted to send him back to Brenner.

After hearing this, Henry gave into the entity's control, letting it possess him as he killed [[Virginia Creel|his mother]] and [[Alice Creel|sister]]. Henry fell unconscious from exhaustion, but eventually awoke later that night and headed to Hawkins High, as he had learned Dr. Brenner was attempting to find [[Patty Newby|Patty]]. A confrontation between Henry, Patty and Brenner then took place at Hawkins High atop the stage of [[Joyce Byers|Joyce Maldonado]]'s attempted school production of ''{{w|Dark of the Moon (play)|Dark of the Moon}}''. Brenner tried to convince Henry that Patty was his weakness while Patty desperately told Henry to ignore him. With Henry feeling overwhelmed, the shadowy entity once again took control of Henry, and Henry threw Patty off the stage. After this, Henry fell unconscious once more, and Brenner took him back to Hawkins Lab. Patty survived and was later hospitalized.<ref name = "fs" />

===1979-1983===
==== The discovery ====
On {{date|September 8|1979}}, a much older [[Vecna|Henry Creel]], now an orderly at Hawkins Lab, entered a psychokinetic duel with test subject [[Eleven]] in the lab's [[Rainbow Room]]. Eleven ultimately overpowered Henry, sending him through [[Gates|a gate]] to [[Dimension X|a mysterious alternate dimension ("Dimension X")]]: a realm defined by mountainous terrain and electrical storms. Though the [[Stranger Things: The First Shadow|alternative account]] of Henry's life showed that Henry had visited this dimension once before as a child, Henry seemed to have no memory of this as an adult.<ref name = "fs" />

Henry began to traverse the alien terrain, encountering “so many things”, including [[Demogorgon (species)|a species of faceless humanoid predators]]. Eventually, Henry discovered “the most extraordinary thing of all”: a dormant, living organism made up of swirling, storm-like particles.<ref name="x" /><ref name = "S04E09teleplay" /><ref name="dormant">[https://www.instagram.com/reel/CgCld2VF_w4/?igshid=MzRlODBiNWFlZA%3D%3D @michael_maher_jr] on Instagram</ref>
[[File:Birth of the Mind Flayer - S4E9.png|thumb|center|<center>[[Vecna|Henry]] moulds the mass of mist into the Mind Flayer</center>|300x300px]]{{TransDivider}}
Using his abilities, Henry formed a psychic connection to the particles. He used his powers to reconstitute the mist-organism into a form that satisfied him: a giant, spider-like entity with a flame-shaped head (not unlike a similar fantasy creature he had imagined as a child). In time, this being would come to be known as the '''Mind Flayer'''.{{Epref|34}}

==== A familiar figure ====
When Henry initially encountered the shadowy entity, the entity first - either literally, or just in Henry's visions - adopted the voice and form of [[Alice Creel|Alice]], [[Virginia Creel|Virginia]] and [[Victor Creel|Victor]] before eventually adopting the persona of [[Martin Brenner|Dr. Brenner]]. The entity claimed it wanted to "study" Henry, and that he was the "most magnificent thing" it had ever encountered. The entity encouraged Henry to take control of the various Demogorgons that roamed the landscape, which Henry achieved by systematically penetrating the mind of each individual creature.

Henry and the entity developed a complicated relationship via psychic connection; Henry repeatedly attempted to seize full control over the entity and the hive mind, but the entity would retaliate, forcing Henry to re-experience troubling memories.<ref name = "VR">''[[Stranger Things VR]]''</ref>

===1983-1984===
==== The Demogorgon's attacks ====
On {{Date|November 6|1983}}, [[Mothergate|the Mothergate]] opened at [[Hawkins National Laboratory|Hawkins Lab]], allowing {{UD}} - a realm somehow related to [[Dimension X]] - to begin to spread through. [[Will Byers]], a young resident of [[Hawkins]], was captured by a [[The Demogorgon|Demogorgon]] and brought to the Upside Down's version of the town's [[Hawkins Public Library|public library]]. Although he was safely recovered by friends and family, Will began to have visions of the Upside Down.

Will continued to have visions of the Upside Down for a year following his rescue. These visions were examined by [[Sam Owens|Dr. Sam Owens]] at Hawkins Lab, who believed Will was experiencing post-traumatic stress disorder.

=== 1984 ===

==== Possession of Will Byers ====
On {{date|October 29|1984}}, Vecna began acting through the Mind Flayer in his first attempt to conquer the world and exterminate humanity. 

That night, Will and his friends went to play at the [[Palace Arcade]]. While his friends argued with the [[Keith|arcade's employee]], Will became distracted by another vision. He walked out of the Upside Down version of the arcade. To his horror, he witnessed a blood-red storm raging in the sky above, before hearing an unearthly howl. However, Will's friend [[Mike Wheeler]] snapped Will out of the vision.

The {{date|October 30|84|following morning}}, Hopper was called to [[Merrill Wright]]'s farm to investigate a strange rot that had decimated the entirety of the [[Merrill's pumpkin patch|pumpkin patch]]. 
[[File:MADMAX - Will sees the Mind Flayer.png|thumb|right|<center>Will first sees the Mind Flayer|240x240px]]
[[File:Season2MonsterDrawing.png|thumb|right|<center>Will's drawing of the Mind Flayer|240x240px]]
Will had another vision later that day. He went to have a bathroom break in the middle of the night and was returning to his bedroom. However, he saw a red light illuminating the walls of his house. The front door swung open, revealing the Upside Down beyond it, where the red storm violently raged once again. Will walked out into the Upside Down and witnessed the obscured but distinctive silhouette of the Mind Flayer, or "shadow monster", amongst the clouds.

On {{date|October 31|84|Halloween night}}, Will experienced yet another vision while trick-or-treating in Loch Nora, finding himself in the Upside Down version of the neighborhood. At first, Will heard a strange chittering sound coming from multiple directions. Then, he watched in horror as the shadow monster rose high into the air before pursuing him through the neighborhood. Will hid behind a wall, unaware that the creature was close behind him. However, Mike found Will and snapped him out of the vision before the shadow monster could touch him.

The {{date|November 1|84|next day}}, Hopper told Owens that the lab must investigate the rot that decimated Merrill's pumpkin patch, suspecting it was tied to the Upside Down. Owens initially resisted, insisting the breach was "contained", but eventually acquiesced to Hopper's demands. Upon extracting and experimenting upon the soil from the pumpkin patch, Owens were shocked to learn much of the soil seemed to come alive when exposed to heat, each sample forming a swirling, silver mass of particles trapped within various beakers.
[[File:S2E3-Mind Flayer reaching.jpg|thumb|left|<center>The entity reaches an 'arm' out to Will|240x240px]]
[[File:Mind Flayer possessing Will.png|thumb|left|<center>The particles possess Will{{TransDividerCustom|30}}|240x240px]]
Will's next vision took place at [[Hawkins Middle School|school]], shortly after he encountered [[D'Artagnan|Dart]] in the bathroom. Will found himself in the Upside Down once more, standing in the school corridor. Suddenly, the shadow monster's dark mist began to flood into the corridor before chasing after Will. After running outside and onto the field, Will stopped and turned to see the shadow monster looming high above the school. Remembering what [[Bob Newby|Bob]] had told him as they drove to school, Will attempted to confront the shadow monster, yelling at it to "go away!" The shadow monster ignored Will, continuing to pursue him before entrapping him within one of its tornado-like appendages.

From that point on, Will gradually became possessed by the shadow monster. His body temperature dropped and he developed an aversion to heat. He also began experiencing what he called "now-memories", where he could see and know what the shadow monster did. In order to better explain his now-memories, Joyce asked Will to draw what he saw. He began frantically drawing what at first appeared to be random scribbles, but Joyce and Hopper soon realized that the drawings were all connected. After assembling the drawings in the correct order, they discovered the drawings depicted a strange maze-like pattern.

Believing the drawings to depict the Upside Down's vines, Hopper went back to Merrill's pumpkin patch. By digging into the earth, Hopper discovered the existence of the underground tunnels, overgrown with [[vines]] and other organic material from the Upside Down. While traversing the tunnels, Hopper became entrapped in vines, unable to escape. Will learned of his predicament through his connection with the shadow monster, and with the help of [[Bob Newby]], they were able to pinpoint his location within the tunnels. After Joyce and Bob successfully freed Hopper, soldiers from the lab arrived and urged them to leave. As the soldiers began burning the tunnels, Will suddenly collapsed and began convulsing on the ground.
[[File:Chapter Six - The Spy.png|thumb|right|<center>Dr. Owens inspects Will at Hawkins Lab|240x240px]]
Will was taken to the lab were he was quickly sedated. When Will awoke, he could not remember Owens, Bob, or Hopper, and was barely able to remember Mike. In a test involving a severed vine from the Upside Down, Owens asked if Will could feel anything as another scientist used a blowtorch to burn the vine. Through this, they determined that Will had some sort of “virus” that connected him to all other infected hosts in a hive intelligence.

==== Using the Demodogs ====
Claiming he knew of a way to beat the shadow monster, Will pointed out a location in the tunnels, saying "he doesn't want me to see there." As the soldiers entered the tunnels, Will revealed that the shadow monster had forced him to deceive them. The soldiers were ambushed and killed by a pack of adolescent Demogorgons called [[Demogorgon (species)|"Demodogs"]]. Shortly after, Demodogs began invading the lab. While the group was escaping the lab, Bob was tackled and killed by several Demodogs. Everyone else, excluding Owens who had stayed behind, managed to escape the lab.

While speculating the shadow monster's weakness, Lucas, Mike, Dustin, and Max theorized that if they destroyed the monster, they would also destroy the monster's army. When they realized that the shadow monster controlled everything in a hive mind, they compared it to the Mind Flayer, a monster from ''[[Dungeons & Dragons]]'' that similarly controls the minds of its victims. The boys' ''D&D'' manual also stated that the Mind Flayer's goal was to spread and take over other dimensions, making them speculate that the shadow monster wanted to do the same. The group decided to interrogate Will to find the shadow monster's weakness.

After making the backyard shed unrecognizable, they placed Will inside and attempted to interrogate him. While the Mind Flayer had taken over a majority of Will's mind and body, a part of Will managed to subconsciously signal to them in Morse code. Deciphering his message, they discovered how to stop the Mind Flayer: they had to close the Gate. Soon after, the phone in the Byers' kitchen rang, giving away their location. A pack of Demodogs quickly surrounded the house, but before they could attack, Eleven arrived and eradicated the creatures.

==== Closing the Gate ====
After taking Will to [[Hopper cabin|Hopper's cabin]], Joyce, Nancy, and Jonathan restrained him, surrounding him with numerous heaters. This eventually caused the fragment of the Mind Flayer possessing Will to be expelled from his body. The particles fled the cabin, escaping to the abandoned [[Brimborn Steel Works]] to lay low.

[[File:Eleven closes the Mothergate.png|thumb|right|250px|<center>Eleven closes the Gate</center>]]
[[File:Mind Flayer hovering the Hawkins Middle School.png|thumb|right|250px|<center>The Mind Flayer looms above Hawkins Middle</center>]]
Hopper guided Eleven through the lab to the Gate, so that she may finally close it for good. Drawing on all her strength and pain, Eleven successfully used her powers to seal the rift. Vecna and the Mind Flayer's psychic link to the human world was cut off, causing the Demodogs and the tunnel-organism to die. The particles of the Mind Flayer’s fragment scattered across the floor of Brimborn Steel Works: dormant, but not destroyed.

On {{date|December 15|84}}, during the [[Snow Ball]], the Mind Flayer loomed over the Upside Down version of Hawkins Middle School, sensing Eleven's presence on the other side.
{{Clear}}
===1985===
{{MainArticle|pagename=[[The Spider Monster]]}}
{{TransDividerCustom|15}}
==== The Soviets' gate ====
On {{date|June 28|1985}}, a [[Starcourt Base|secret Russian operation]] located beneath Hawkins' newly-built [[Starcourt Mall]] successfully opened [[The Keys|another Gate]] into the Upside Down. Soviet-owned properties in East Hawkins, all near transformers, were used to siphon off energy from the town's power grid, triggering a major power outage. The energy was redirected to the underground base, and channelled into the Key. The Key ray activated and fired into the base wall, with a gate successfully forming. In the days that followed, the Soviets were able to acquire creatures and genetic material from the Upside Down; they even captured a fragment of the Mind Flayer and a pack of Demodogs, which were incapacitated and shipped to [[Kamchatka Facility|a facility]] in [[Kamchatka|the Kamchatka Peninsula]]. The Demodogs were kept paralysed in tanks filled with oxygenized water, and the Mind Flayer fragment was entrapped in a special cell covered with heating devices in the facility, directly adjacent to the room containing the Demodogs.

==== The Flaying ====
[[File:The melting rats.jpg|thumb|right|220x220px|<center>Rats gather at the Steel Works</center>]][[File:S03E02 Official Image.jpg|thumb|right|220x220px|<center>Billy sees the Upside Down</center>]]

After the gate was successfully formed, the Upside Down's psychic link to Hawkins was also re-established, reviving the fragment of the Mind Flayer laying low at [[Brimborn Steel Works]]. The cloud of particles began possessing hordes of rats, and had them consume different types of chemicals; many of the rats would then explode into bloody puddles of biomass to create a [[The Spider Monster|proxy form]], through which Vecna (via the Mind Flayer) could operate in the human world.  

While driving down Cherry Oak Drive, [[Billy Hargrove]] suddenly found himself attacked by an unseen force, causing him to crash his car. Billy left the vehicle to investigate, coming across the abandoned Steel Works nearby; suddenly, a giant tendril emerged out of nowhere and dragged Billy into the shadows. In the basement of the Steel Works, the rat-flesh creature pumped toxic material into Billy's face and infected his mind, converting him into an obedient servant. Billy hallucinated himself leaving the building, only to find himself in the Upside Down; he saw a number of shadowy figures appear in the distance, and tried to call out to them. One of the figures walked forward; Billy was shocked to realize he was looking at a mirror image of himself who told to "build what he saw".

[[File:Stranger-Things-season-3-screenshots-Chapter-3-The-Case-of-the-Missing-Lifeguard-129.jpg|right|thumb|<center>The possessed Billy's eye formulating black veins|240x240px]]

The {{date|June 30|85|next day}}, a mind-addled and disturbed Billy kidnapped his co-worker [[Heather Holloway]] and took her to the Steel Works, where she too became possessed by the creature. Over the next few days, dozens more people were 'Flayed', including [[Doris Driscoll]] and [[Bruce Lowe]]. [[The Flayed]] would often target those close to them, such as Heather's parents, [[Tom Holloway|Tom]] and [[Janet Holloway|Janet]]. In some cases, such as with [[Doris Driscoll]], exposure to infected rats was enough to bring the individual under the Mind Flayer's thrall. As with the rats, the unfortunate humans would be made to gorge cleaning fluids and other toxic chemicals, which would seemingly boost the infection's grip upon their minds. Some of these individuals would later dissolve into biomass, and reconstituted into [[Flesh Thralls|fleshy monstrosities]] directly under the hive mind’s control. 

Eleven and her friends began investigating Billy after they realised he had been acting strange; after confronting him at the [[Hawkins Community Pool]], the group realised he had fell under the Mind Flayer’s control. Later, Eleven used [[The Void|psychic projection]] to locate Billy after he escaped their encounter. However, to Eleven’s surprise, Vecna was aware of her presence within Billy's mind, and placed her in a hallucination; using Billy as a vessel, Vecna talked to Eleven and learned of her location. However, in this moment of psychic connection between Eleven, Billy and Vecna, Eleven also saw Billy’s childhood memories, and learned of his troubled past.<ref name = "4ending" />

[[File:MindFlayerseason3.JPG|thumb|right|230x230px|<center>The Tom-Bruce amalgam</center>{{TransDividerCustom|80}}]]

Meanwhile, Vecna had the Mind Flayer melt down the bodies of the Flayed; [[Hospital Monster|a new monster]] was created from the melted remains of Tom Holloway and Bruce Lowe, which in turn merged with the proxy creature at the Steel Works. Eventually, all of the Flayed were summoned to the Steel Works, where all except Billy were melted and absorbed into the rat-flesh creature. The giant spider-like creature, not dissimilar in appearance to the "shadow monster", broke threw the roof of the Steel Works and began to hunt down the Party, knowing they were at Hopper’s cabin. the Party and their allies were viciously attacked, but largely succeeded at defending themselves; however, a small piece of the proxy monster detached itself and bit into Eleven's leg, severely wounding her.

==== The battle of Starcourt Mall ====
Later {{date|July 4|85|that night}}, Eleven's group went to Starcourt Mall to find [[Dustin Henderson|Dustin]], who had apparently located a new gate to the Upside Down. Shortly after meeting with Dustin and his friends in the food court, Eleven suddenly writhed in pain and fell to the ground; the group realised a piece of the flesh creature was still embedded in her wound. [[Jonathan Byers|Jonathan]] forced the creature out, escaping before being dramatically crushed underfoot; Hopper, Joyce and their friend [[Murray Bauman]] had arrived at the mall, who hoped to infiltrate the Russian base and destroy the gate. Taking what Dustin, [[Steve Harrington|Steve]], [[Robin Buckley]] and [[Erica Sinclair]] had learned from [[Scoops Troop|their own adventure]] inside the base, Hopper, Joyce and Murray travelled there via the secret elevator their younger allies had discovered. After gunning down various Soviet soldiers, the trio took and donned their military uniforms, going incognito as they entered the facility.  

In the food court, Eleven was unnerved to discover she had seemingly lost her psychokinetic abilities, leaving her and her friends vulnerable to the monster's attack. Not long after, Billy and the flesh monster arrived at the mall, still intent on destroying Eleven. After some time, Billy captured Eleven and dragged her to the middle of the food court, where she was to be consumed by the flesh monster. In a last-ditch effort to stop them, the kids started launching fireworks at the creature. Eleven tried to break through to Billy's conscience while the creature was distracted, talking through his memories in an attempt to connect with him. The strategy worked: Billy's long-dormant humanity re-awakened within him.  

[[File:S3E8 Spider Monster kills Billy2.png|thumb|right|230x230px|<center>The Spider Monster kills Billy</center>]]
[[File:S3E8 - Spider Monster10.png|thumb|right|230x230px|<center>The creature’s corpse</center>]]

After the fireworks fizzled out, the proxy monster regained its composure; it launched a spiked tendril directly at Eleven, only to be intercepted by Billy. The creature, enraged by Billy's betrayal, launched a dozen more tendrils at him, fatally wounding him. At the same time, Hopper and Joyce reached the Soviet control room and disabled the Key machine. Hopper was thought to have perished in the process, but had survived by escaping to another platform within the same room. He was soon captured by Soviet forces. 

Following the machine's deactivation, and the gate's closure, the psychic link to the Upside Down was cut off once again, causing the flesh monster to collapse and become inanimate. The creature's corpse fell into the hands of either the American or Russian government, or alternatively, burned up in the "mall-fire" that apparently broke out following the battle's conclusion. The US military arrived to assess the aftermath and stormed the Soviet base; Dr. Owens reached the room containing the Key, and surveyed the smoldering remains of the shut gate. 

===1986 ===

==== Vecna's plan ====
When Vecna emerged as a new threat to Hawkins in {{year|1986}}, Dustin believed that he was essentially the Mind Flayer's "five-star general". Later, Vecna targeted [[Nancy Wheeler]] with the sole purpose of sending Eleven a message. He subjected Nancy to various disturbing visions, including a "giant creature with a gaping mouth" looming over Hawkins.{{epref|33}}

==== The Demogorgons in Russia ====
[[File:Mind Flayer tank.jpeg|thumb|Hopper finds a tank containing animate particles of the Mind Flayer.]]
Meanwhile, Jim Hopper, having been [[Kamchatka Facility|imprisoned]] in [[Kamchatka]], narrowly escaped the wrath of a [[Russian Demogorgon|Soviet-controlled adult Demogorgon]], and was broken out of captivity by Joyce, [[Murray Bauman]] and [[Yuri Ismaylov]]. After Hopper and his ally [[Dmitri Antonov]] were freed, the group discovered a cell containing a piece of the Mind Flayer, which they called 'the particles'. In the same room, the group discovered dozens of juvenile Demogorgons, paralysed and stored in tanks. After the group's exit from the facility, the situation involving the unleashed Demogorgon became more and more chaotic. As Soviet soldiers haphazardly fought the creature, they accidentally shattered the cell holding the captured portion of the Mind Flayer. These released particles immediately entered the bodies of the paralysed Demodogs, reawakening and possessing them, and going on to slaughter the remaining personnel. 

Hopper and his allies returned to the base, hoping that destroying the particles in the cell could inflict damage to the Upside Down's hive mind, and therefore assist in the conflict simultaneously occurring in Hawkins. After learning what had happened since their escape, the group started fighting the possessed creatures, still hoping to inflict pain on the hive mind. After chasing Hopper and Joyce around the Soviet base for a lengthy period, the Demogorgons gathered in the same spot, allowing Murray to burn the bulk of them to death with Yuri Ismaylov's flamethrower. The fully grown Demogorgon survived, but moments later, Hopper used [[Minor Items|a sword]] to behead the creature. The deaths of the Demogorgons weakened everything else connected to the hive mind: the bats, the vines, and even Vecna himself. By executing the Demogorgons, the group seemed to destroy various fragments of the Mind Flayer, or otherwise rendered its particles unusable.

==Incarnations==
=== The Shadow Monster ===
[[File:S2E2-Mind-Flayer-emerging7.jpg|thumb|280x280px|<center>The Mind Flayer looms above Loch Nora</center>]]
[[File:Mind Flayer inital form.png|thumb|280x280px|<center>The Mind Flayer's initial form</center>]]
The Mind Flayer's main form, also known as the "Shadow Monster", is a massive entity, looming at least 50 stories tall.<ref name=":0" /> It has a unique body composed entirely of minuscule particles, giving it a misty appearance akin to a shadow.  

Originally, the particles took the form of a swirling, storm-like mass, which Henry Creel manipulated and reformed into the Mind Flayer. The Mind Flayer had a vaguely spider-like appearance, due to Henry's love of [[Black widows|black widow spiders]]. The entity has numerous tornado-like limbs, some of which branch into several smaller appendages, and is visually reminiscent of the [[vines]] that overrun the Upside Down. The body also features an elongated, flame-shaped head that sprouts from the central body. The creature's presence is often accompanied by unnatural red lightning, which Will describes as a "storm". 

Through a telepathic link, Vecna, via the Mind Flayer, could directly control additional entities and beings:

===The Particle Fragments===
[[File:Brimborn fragment.png|thumb|250x250px|<center>The fragment of the Mind Flayer at [[Brimborn Steel Works]]</center>]]
Pockets of the Mind Flayer’s silver-black mist could move independently while remaining connected to the hive mind and under Vecna’s control. 

One of these pockets left the main body and latched itself onto Will Byers, allowing Vecna and the Mind Flayer to possess him. Will's friends and family eventually forced the creature to abandon Will, with the mist fragment flying away to [[Brimborn Steel Works]]. When the [[Mothergate]] was closed, these particles fell dormant, scattering across the mill's floor. The mist fragment eventually re-awakened when [[The Keys|a machine]] created a new [[Gates|gate]] in the summer of 1985, renewing the mist fragment's telepathic link. The reanimated particles quickly infected and summoned hordes of rats to the Steel Works, [[The Flayed|"Flaying"]] them and melting down their bodies into [[Flesh Thralls|biomass creatures]], which were combined to create [[The Spider Monster|a proxy form]].

[[File:Flayer fragment.png|thumb|250x250px|<center>The trapped Mind Flayer fragment at [[Kamchatka]]</center>{{TransDividerCustom|80}}]]
A separate piece of the Mind Flayer was captured by Soviets and stored at a [[Kamchatka Facility|prison camp]] in [[Kamchatka]]; it was presumably extracted via the Soviets' gate to the [[the Upside Down|Upside Down]] at [[Starcourt Base|their base]] under [[Starcourt Mall]]. However, after a [[Russian Demogorgon|captive adult Demogorgon]] broke free and rampaged the prison, the tank containing the Mind Flayer's particles was shattered in the ensuing gunfire, allowing the particles to possess a number of paralysed [[Demogorgon (species)|Demodogs]] in tanks. The various Demogorgons then continued to wreak havoc on the base, killing the vast majority of the staff. When [[Jim Hopper|Hopper]], [[Joyce Byers|Joyce]] and [[Murray Bauman|Murray]] returned to the base, they learned from the dying [[Warden Melnikov]] that "the shadow" had escaped and had "entered" the Demogorgons. Later, Murray burned the bulk of the creatures to death with [[Yuri Ismaylov]]'s flamethrower, with Hopper beheading the adult Demogorgon with a sword. With each creature killed, a piece of the Mind Flayer was also destroyed.  
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=== The Spider Monster ===
{{MainArticle|pagename=[[The Spider Monster]]}}
{{TransDividerCustom|15}}[[File:St mind flayer.png|thumb|280x280px|<center>The Mind Flayer's proxy</center>|link=[[The Spider Monster]]]]
The [[The Spider Monster|Spider Monster]], the Mind Flayer's 1985 proxy body, resembled a gargantuan, monstrous spider. This incarnation of the Mind Flayer closely matches its Upside Down counterpart in terms of its shape and proportions. However, unlike the Flayer's main body, the Spider Monster is not shrouded in silver-black mist, nor is it as large (though it still stands tall at over 20 feet in its fully-formed state). The Spider Monster is nigh on indestructible but remains vulnerable to heat.

The Spider Monster is composed of the bodies of [[the Flayed]]: dozens of organisms, both human and otherwise, whose bodies were biologically converted to serve the Mind Flayer's will. The Spider Monster was originally relatively small, being composed purely out of Flayed rodent bodies; however, it rapidly grew after finally consuming the converted humans.

===The Hospital Monster and the Flesh Thralls===
{{MainArticle|pagename=[[Hospital Monster]] & [[Flesh Thralls]]}}
{{TransDividerCustom|15}}[[File:MindFlayerseason3.JPG|thumb|280x280px|link=[[Hospital Monster]]]]
In 1985, the Mind Flayer created [[Flesh Thralls|an army of smaller entities]] that served the Spider Monster. They were composed entirely of flesh, cartilage and bone, just like the Spider Monster. The thralls were biological reconsitutions of possessed or "flayed" creatures, including rats and humans. The thralls could merge with one another to form larger monsters.

The most notable of these was the [[Hospital Monster|"Hospital Monster"]], composed of Flayed humans Tom Holloway and Bruce Lowe. Unlike the Spider Monster, the Hospital Monster only vaguely resembled the Shadow Monster, and had a more asymmetrical appearance. The creature was ultimately absorbed into the Spider Monster.
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===The Shadowy Figure===
[[File:Shadow Brenner.png|thumb|200x200px|<center>The entity adopts the form of [[Martin Brenner|Brenner]]</center>]]
When Henry initially encountered the shadowy entity, the entity first - either literally, or just in Henry's visions - adopted the voice and form of [[Alice Creel|Alice]], [[Virginia Creel|Virginia]] and [[Victor Creel|Victor]] before eventually adopting the persona of [[Martin Brenner|Dr. Brenner]]. The entity claimed it wanted to "study" Henry, and that he was the "most magnificent thing" it had ever encountered. However, the relationship between Henry and "Shadow Brenner" soon grew fractious, with both vying for dominance over the [[hive mind]].<ref name = "VR" />
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==Nature==
When {{UD}} first emerged as a threat in {{year|1983}}, it was believed that [[the Demogorgon]] was potentially the dimension's sole inhabitant, with [[Nancy Wheeler]] noting that the creature's hunting patterns were "solitary".{{epref|6}} However, in {{year|1984}}, other creatures and entities began to emerge. [[Sam Owens|Dr. Sam Owens]] and the other scientists at [[Hawkins National Laboratory|Hawkins Lab]] observed that all lifeforms native to the Upside Down - including the pack of [[Demogorgon (species)|adolescent Demogorgons]] which attacked the lab - were linked through a shared [[hive mind]].{{epref|14}} [[Will Byers]], who had become connected to the hive mind, experienced visions of being attacked by a giant shadowy entity, who Will called a "he"; Will was later possessed by the entity for a short period. The [[The Party|Party]] initially concluded that the entity - which they nicknamed [[Dungeons & Dragons#Mind Flayer|"the Mind Flayer"]] after an anatagonist from ''[[Dungeons & Dragons]]'' - was the force that commanded the hive mind.{{epref|16}}

From 1984 to 1986, the Party and their allies tended to call the Mind Flayer "him" and "he". They knew little else about the creature, besides 'his' intention to eradicate humanity and merge the human world with the Upside Down; they believed the Mind Flayer was the entity who possessed [[Billy Hargrove]] and [[the Flayed]] in {{year|1985}}.

In {{year|1986}}, [[Vecna]] declared himself as the true ruler of the Upside Down to [[Eleven]], explaning how he had refashioned the Mind Flayer entity into its current form upon discovering it in [[Dimension X]], apparently taking control of it (and the hive mind) in the process. After this, Will realized the 'he' who possessed him back in 1984 was actually Vecna, with the Mind Flayer only acting as an extension of his will.{{epref|34}}

However, despite Vecna claiming supreme control over the hive mind, the relationship and power dynamic between him and the Mind Flayer seemed extremely ambiguous. The dormant cloud of silver-black mist - from which Henry created the Mind Flayer's spider-like "shadow monster" form - was already a living organism.<ref name="x" /><ref name = "S04E09teleplay">[https://static.wikia.nocookie.net/strangerthings8338/images/a/a8/20145-Stranger-Things-Episode-409-by-Matt-Duffer-and-Ross-Duffer.pdf/revision/latest?cb=20230523074046 The official teleplay for "The Piggyback"]</ref> Multiple accounts depicted the entity as having [[The Mind Flayer#The Shadowy Figure|a sentience and intelligence]] all of its own. [[Stranger Things: The First Shadow|One of these accounts]] even suggested that the entity was the source of Henry's powers, with Henry being exposed to its influence when he was accidentally transported to [[Dimension X]] as a child. Upon returning home, the sentience forced Henry to murder his [[Creel family|family members]]. Though [[Stranger Things VR|one account]] depicted the sentience vanishing after Vecna reformed the mist into the Shadow Monster, it was not necessarily clear if the sentience had been destroyed or defeated. Similarly, even though Henry apparently encountered the entity as a child, Henry did not seem to recognize the entity when re-encountering it as an adult; this could be read as a sign of his "broken memories".<ref name= "fs" /><ref name= "VR" /><ref name="indiewire">[https://www.indiewire.com/2022/05/stranger-things-season-4-vecna-vfx-1234729087/ "‘Stranger Things’ Season 4: How the Duffer Brothers Channeled Freddy Krueger for the Vecna Monster"] ''IndieWire''. May 31, 2022.</ref>

While a massively powerful being, the Mind Flayer was not without weakness. Most notably, it had a low tolerance to heat, particularly fire. All hosts within its hive mind shared this weakness, resulting in the creature feeling pain whenever a connected entity was exposed to heat, or burned.{{epref|13}}{{epref|17}}

==Powers and abilities==
===The hive mind===
With the Mind Flayer at his side, Vecna's powers greatly expanded. The Mind Flayer's body could split into smaller pieces while sharing a collective consciousness. These smaller pieces could possess other creatures and beings, tying them to the same core consciousness; through the Mind Flayer, Vecna could connect various lifeforms to a shared hive mind, with Vecna's will at the top of the chain. Through the hive mind, a diverse range of beings fell under Vecna's control, including [[Demogorgon (species)|"Demogorgons"]], [[Will Byers]] and the [[Hawkins Tunnel System|tunnel-organism]] in 1984, [[The Flayed|the "Flayed" of 1985]], and [[Demobats|"Demobats"]], as well as [[Vines|the roots and vines]] strewn across the surface of the Upside Down.

Furthermore, through his command of the hive mind, Vecna approached a near-omniscient understanding of his territory. If a Demobat became aware of a trespasser in the Upside Down; Vecna would instantly know. Similarly, if an unlucky visitor were to tread on a vine, Vecna could immediately react and disseminate his will, making the vines spring into action and attack. However, at times, Vecna's connection to his thralls proved to be [[The Mind Flayer#vulnerability|a glaring vulnerability]].</span>

=== Resilience ===
Pieces of the Mind Flayer could only operate when psychically linked to the Upside Down's hive mind (via [[Gates|a gate]]). However, if the gate closed, the Mind Flayer's particles wouldn't die, unlike the [[Demogorgon (species)|Demogorgons]], or the [[The Spider Monster|Spider Monster]]. The particles would instead scatter and turn dormant; if and when a new gate was opened, the particles could immediately reconnect with each other and continue to serve the hive mind's will.

=== Weather manipulation ===
The Mind Flayer's presence was almost always accompanied by atmospheric disturbances. In the Upside Down, dark storms would rage in the skies above, with startling red lightning shooting across, illuminating the whole dimension in scarlet light. The storm seemed to be linked to Vecna's emotions; the Mind Flayer was seen looming over Hawkins Middle School, seething with Vecna's anger.

=== Power negation ===
After biting her with one of its tentacles, the Mind Flayer's proxy left a piece of itself inside Eleven, severely weakening her telekinesis later that evening; her powers would eventually fade completely, and would not be restored until [[The Nina Project|the events of March 1986]].

=== High speed travel ===
Due to consisting entirely of particles, the Mind Flayer - either in its shadow form, or acting as a fragment - could move incredibly quickly, soaring through the atmosphere at high speed.

==Weaknesses==
=== Heat ===
Prolonged exposure to high temperature can weaken the Mind Flayer. When Will Byers was exposed to high temperature, it forced the fragment of the Mind Flayer within Will to flee his body. Similarly, when soldiers set [[Hawkins Tunnel System|the tunnels]] aflame, the possessed Will writhed in pain.

=== Dimensional barrier ===
The [[Fabric of space-time|dimensional barrier]] puts hard limits on the Mind Flayer's ability to take over other worlds. However, if the barrier is damaged, the Mind Flayer is able to exert more and more influence in another dimension.

<span id="vulnerability">
=== The hive mind ===
Though Vecna's control of the Mind Flayer's hive mind [[The Mind Flayer#Powers and abilities|made him powerful]], the two-way nature of the psychic connection was also a point of vulnerability. Any pain felt by the connected entities was shared amongst them; the physical suffering of his thralls would translate to every other being in the hive mind, including Vecna himself. This made the hive mind a prime target for his enemies.</span>

==Relationships==
{{Relation|Vecna|Vecna/Henry Creel}}
The Mind Flayer had a complex relationship with Henry Creel; it was not necessarily clear which being had a greater influence over the Upside Down and its hive mind.

When Vecna initially re-emerged as a threat to Hawkins in 1986, Dustin believed he was akin to the Mind Flayer's "five-star general". However, when Vecna psychically trapped Eleven within his Mind Lair, Vecna told Eleven that he had been control of the Upside Down the entire time. Vecna explained that he had discovered a dormant version of the Mind Flayer entity upon being trapped in Dimension X, describing it as "the most extraordinary thing of all". Using his psychic powers, Henry gave the Mind Flayer its gigantic, spider-like form and established a psychic connection with the entity, forming a kind of symbiotic relationship. Furthermore, Vecna had apparently been acting through the entity in both 1984 and 1985.

However, according to one account, the relationship between Henry and the entity began much, much earlier, in the 1950s. According to this account, Henry spent much of his childhood living with his family in Rachel, Nevada. One day, Henry explored a nearby cave system while playing with a spyglass. While exploring, Henry stumbled across pieces of scientific equipment stolen from the Nevada Experiment. The equipment unexpectedly activated; Henry and the scientist who stole the equipment were temporarily transported to Dimension X, killing the scientist in the process. In the alternate world, Henry was exposed to the influence of the Mind Flayer entity; from that point on, the entity served as a negative influence on Henry, forcing him to kill various animals and eventually kill his family members.

For reasons unclear, Henry seemed unaware of the entity's influence over him when he spoke in 1979 and 1986, with him describing how he consciously chose to kill his family, and that he had apparently never been to Dimension X before 1979. Though Vecna clearly believed he controlled the hive mind, Dustin's initial assumption that Vecna served as the Mind Flayer's five-star general was possibly accurate after all, even if Vecna himself didn't realise it.

{{Relation|Eleven}}
It seemed the Mind Flayer held a deep-seated grudge against Eleven, ever since she closed the Mothergate in 1984. However, the Mind Flayer was later discovered to merely be Vecna's puppet. The entity would likely be totally indifferent towards Eleven, were it not for Vecna's influence.

{{Relation|Will Byers}}
When Will was trapped in the Upside Down and captured by a Demogorgon, the Mind Flayer became interested in Will and decided to use him for his own purposes, showing no care for him. After Will's rescue, the Mind Flayer started spreading the Upside Down through Hawkins where Will was given visions of the Upside Down. The Mind Flayer eventually confronted Will and started to seek him as a vessel in order to use him to pave into the real world. The Mind Flayer was thwarted two times by Will's friend, [[Mike Wheeler|Mike]], but when Will finally decided to confront the Mind Flayer, he became possessed by a piece of the Mind Flayer. The Mind Flayer slowly took over Will's body and mind, allowing to see and feel everything the Mind Flayer was doing. After Will took advantage of his possession to rescue [[Jim Hopper]] where the tunnels were burned by the government soldiers, the Mind Flayer used his possession of Will, forcing him to trick the soldiers into going a trap, as revenge for hurting him through the burning of the tunnels. The Mind Flayer tried to keep his control over Will intact but was stopped by Will's family and [[Nancy Wheeler]] as they burned the Mind Flayer out of Will.

A year later, in 1985, despite being freed from the Mind Flayer, he left a huge impact on Will as he could still sense the Mind Flayer's presence whenever he was close. Nevertheless, The Mind Flayer did not seem to remember Will, or harbor any resentment toward him. However, the piece of the Mind Flayer that possessed Will constructed a body for himself out of rats and the Flayed so he could kill Will and his friends as revenge for the events in 1984. However, his plans were thwarted when [[Joyce Byers]] closed the Gate, killing the Mind Flayer's proxy body.

In 1986, Will finally discovered the Mind Flayer to be Vecna's puppet and it was him who had possessed him through the Mind Flayer. Will remarked it was bizarre discovering the true culprit behind everything he and his loved ones had been through, but since Vecna had no intentions in giving up in his evil plans, he proposed Vecna had to be killed once and for all. 

{{Relation|Billy Hargrove}}
Upon its return to Earth in 1985, the Mind Flayer lured Billy into its new lair, converting him into the first Flayed and using him to turn other residents of Hawkins, as well. Unlike the rest of the Flayed whom the Mind Flayer had killed to build his proxy body, he kept Billy alive due to his physical strength, and because he was the stepbrother of [[Max Mayfield]], a member of the Party whom Vecna sought to kill as the Party were obstacles in his plans for world domination. The Mind Flayer did not seem to care for Billy as a person and quickly killed him after Billy broke free from its control through the memory of his mother.

==Appearances==
{{Series appearances|s1 = none|9 = yes|10 = yes|11 = yes|12 = yes|13 = no|14 = note|15 = no|16 = no|17 = yes|18 = yes|19 = note|20 = note|21 = note|22 = note|23 = note|24 = note|25 = note|26 = note|27 = no|28 = note|29 = no|30 = no|31 = no|32 = no|33 = yes|34 = note}}
{{LatAppendix|The Mind Flayer appears via flashback in {{Ep|14}}}}
{{LatAppendix|The Mind Flayer appears throughout Season 3 as the [[The Spider Monster|Spider Monster]]}}
{{LatAppendix|The Spider Monster appears via flashback in {{Ep|26}} and {{Ep|28}}}}
{{LatAppendix|The Mind Flayer appears via flashback in {{Ep|34}}}}

===Comics===
{{The Other Side Appearances|no|no|no|yes}}

===Video games===
{{Video Game Appearances|no|yes|yes|no|yes|no|yes|yes|no|yes}}

===Other appearances===
* ''[[Stranger Things: The First Shadow]]''

==Behind the scenes==
===Concept and design===
[[Matt Duffer]] told ''Entertainment Weekly'' that the shadow monster was inspired by horror classics: "There's an [[Influences & references#Books and novels|H.P. Lovecraft]] sort of approach, this inter-dimensional being that is sort of beyond human comprehension."<ref name=":1">"[http://ew.com/tv/2017/09/28/stranger-things-2-new-monster/ Stranger Things 2: Behind the sequel's big, bad 'shadow monster']" ''Entertainment Weekly''. September 28, 2017.</ref>
[[File:Flayer concept art.PNG|thumb|Concept art of Will confronting the Mind Flayer on the field.|240x240px]]
Visual-effects producers Paul and Christina Graff were tasked with designing the creature. Because the first season incorporated several electrical interferences, they knew the second season would involve storms. Once it was decided the monster was "storm-like", the Graffs began reseraching the look of storms and tornadoes. Steve Messing, a matte painter who was also consulted on the designs of several other ''Stranger Things'' elements, created concept art of the creature based on tornadoes, volcanoes, and other natural forces. In addition, they were inspired by volcanic eruptions with lightning storms in South America.<ref name=":0" />

For [[Stranger Things/Season 4|Season 4]]'s 'Dimension X' scene, concept artist [[Michael Maher, Jr.]] pitched that the Mind Flayer particles were "an anti gravity element" that would lift boulders into the air, "effectively falling upwards". However, the idea was scrapped, as it would have taken too long to explain in the context of the story.<ref>[https://www.michaelmaherjr.com/dimension-x DIMENSION-CPT_CPT - MICHAEL MAHER JR]</ref>

===Name===
While the entity was called the Shadow Monster throughout Season 2's production, the Duffers decided they had to give it a more formal name. Looking through the ''Dungeons & Dragons'' manual, they decided to name the Shadow Monster after the "[https://forgottenrealms.fandom.com/wiki/Mind_flayer Mind Flayer]", due to their similarities.<ref>"[http://www.vulture.com/2017/11/the-duffer-brothers-recap-stranger-things-2-the-mind-flayer.html The Duffer Brothers Recap Stranger Things 2, ‘Chapter Eight: The Mind Flayer’]" ''Vulture''. November 8, 2017</ref>

==Trivia==
*The Mind Flayer is the second character to be nicknamed after a character from [[Dungeons & Dragons|''D&D'']], with the first being the [[The Demogorgon|Demogorgon]] and the third being [[Vecna]].
**In ''Dungeons & Dragons'', Mind Flayers are a race of psychic, monstrous humanoids with octopus like heads who eat brains.  They primarily use their powerful psychic abilities to mentally enslave other beings. More recent editions have given the Mind Flayers the proper name "Illithids".
*Possessed humans are colder to the touch than average, to the point where the temperature around possessed humans significantly decreases.
*The scene in which the Shadow Monster infects or enters Will bears resemblance to the possession sequence in 1973's ''The Exorcist''.
*The possessed Billy uses "we" pronouns to refer to itself, suggesting that the Flayed may maintain vestigial traits of individuality even while part of the Mind Flayer's hive mind.
*Despite having [[The Mind Flayer (episode)|an episode]] named after it, the Mind Flayer is not physically present in said episode.
*The Mind Flayer is very similar to the Elder Gods of H.P. Lovecraft, with his work actually tying into the ''Stranger Things'' universe, with Lisa from the novel, ''[[Stranger Things: Darkness on the Edge of Town|Darkness on the Edge of Town]]'', being a graduate of the infamous Lovecraftian college "Miskatonic University".

{{Gallery|pagename = Mind Flayer}}

==External Links==
* [[w:c:turtlepedia:The Mind Flayer|The Mind Flayer]] at TMNTPedia
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