Written before the premiere of Season 5: This post is to discuss my speculations about the truth of the Upside Down from watching Stranger Things over the years, and to see if I got anything right once Season 5 comes out.
Although Stranger Things isn’t a traditional thriller or mystery drama but rather an inspiring story about love and growth,discussions about the truth of the Upside Down have never stopped online since the show’s debut.
From Season 1 to Season 4, I’ve come up with countless explanations, but two theories have consumed the most brainpower.
These two theories took me on a long mental journey: confidently thinking I’d cracked the truth → getting brutally debunked by new plot developments → trying to patch up the flaws but finding more holes → realizing the theory might not hold up → starting over with a new approach. By the end, I was mentally exhausted.
Now, I’m writing them down to share how I gradually drove myself crazy…
The article is kind of long, and I am a foreign fan, please forgive me if I make some grammar or spelling mistakes.
(1) Multiverse Theory, Credibility: ★★★
Before Season 4 aired, my view of the Upside Down was as follows:The Upside Down is essentially a parallel universe similar to the “Rightside Up” world.
Like the parallel world in the show Fringe, it’s inhabited by another group of humans identical to those in our main world.
The Upside Down once had a normal human civilization, just like the Rightside Up (or rather, an identical human civilization).
However, disaster struck one day when this world was invaded by dark creatures from a higher dimension.
All living people were killed (or turned into some kind of meatball by the mindflayer…).
The sky was covered with black matter, turning it into a paradise for dark creatures.
This explains why, in the first three seasons, the Upside Down’s Hawkins looked identical to the Rightside Up’s Hawkins but had no living people because it was occupied by those dark creatures.
But after Season 4 aired, this theory was shattered…
The reason is that when Eleven first opened the gate in November 1979, the Upside Down was a chaotic, primordial wasteland, not the mirror universe resembling the Rightside Up.
But by 1983, the Upside Down had transformed into the appearance of the Rightside Up’s Hawkins, frozen in time on November 6, 1983.
This sudden change caught me off guard. No matter how perfect my previous theory was, the writers could kill it with a single stroke.
But I wasn’t ready to give up on this theory. I wanted to make a final, desperate attempt to salvage it, so I had to confront two fatal issues raised by Season 4:
1. Why did the Upside Down initially look like a primordial Earth wasteland but later transform into the appearance of Rightside Up Hawkins?
2. Why is the Upside Down’s time frozen on November 6, 1983?
After days of thinking, I came up with an even more terrifying possibility…
Could it be possible that there isn’t just one Upside Down-like parallel universe, but multiple ones?
Could it be that the Upside Down Eleven sent Vecna to in Season 4 isn’t the same Upside Down that Will was taken to in Season 1?
Fans of DC, Marvel, or Rick and Morty should be very familiar with the concept of multiple parallel universes. With this hypothesis, let’s start reasoning about the relationship between the Rightside Up and the Upside Down.
There are countless parallel universes in existence.The main universe where the protagonists live, let’s call it Universe A.
Beyond Universe A, there exists a mirror universe very similar to Universe A, which we’ll call it as Universe B.
Both Universe A and Universe B are normal worlds with human civilizations and living people.
In 1979, Eleven and Vecna engaged in a psychic showdown in Hawkins Lab in Universe A.
Ultimately, Vecna was defeated, and Eleven opened a gate, sending him to a chaotic, primordial dark universe…
This dark universe, let’s call it Universe X.
Universe X is a universe completely different from Universe A and Universe B.There’s no human civilization here, only sky-obscuring black spores, terrifying red lightning striking from above, disgusting monsters roaming barren rocky landscapes, and the physical laws seem somewhat different (with massive floating debris in the sky).
Clearly, this is a highly fantastical universe. Vecna used his powers to tame the creatures here and created spider-like mindflayer to serve him. Then, he worked diligently here, searching for a way back to Universe A (to take revenge on Eleven).
After years of practice, Vecna finally found a way to open gates to other universes.But in the vast, infinite multiverse, Vecna got lost…
He didn’t find Universe A but instead found Universe B, which is very similar to Universe A.
Then, through the sacrifice of four victims (just like Season 4), he successfully established a connection between Universe X and Universe B.What happened next should be easy to imagine.
Vecna led an army of dark creatures from Universe X to invade Hawkins in Universe B, killing all the living people and completely taking over,
turning Universe B from this:
To this:
That day was November 6, 1983.
On the same day Universe B fell, Dr. Brenner (Papa) in Universe A forced Eleven to use her powers to explore other parallel universes, and during her psychic “astral projection,” she ran straight into Vecna’s monsters!
Under the pressure of fear, Eleven’s powers went out of control, accidentally opening a gate between Universe A and the Vecna-occupied Universe B, letting the monsters through! (Vecna: “I was looking for you, and you came to me!”)
The monsters then rushed from Universe B into Universe A, kidnapped Will, and took him to Universe B, kicking off the story of Season 1.
Can you grasp the core of this theory? To summarize:
In Seasons 1 and 4, the Upside Down that the protagonists entered is actually the Vecna-occupied Universe B, not the Universe X where Eleven sent Vecna in 1979.
Will, Joyce, and Hopper visited Universe B in Season 1, and the teens visited it again in Season 4, but none of them have been to Universe X.
Vecna initially couldn’t find Universe A, but Eleven’s psychic experiments on November 6, 1983, inadvertently revealed Universe A’s “coordinates,” allowing Vecna to focus on invading Universe A later.
Universe B was conquered by Vecna on November 6, 1983, with all living people in Hawkins disappearing, and human activity frozen on that day. This explains why Nancy’s diary in Season 4 was stuck on November 6, 1983.
Another point: when Vecna invaded Nancy’s mind, she saw Hawkins being destroyed by Vecna. I think Vecna might have replayed his memories of destroying Hawkins in Universe B for her.
Sounds kind of plausible, right? But upon closer inspection, I realized this theory has many issues.
The first issue: the timeline feels too rushed…
Nancy in Universe B wrote her last diary entry on November 6, 1983, and then vanished.Diaries are usually written at night, meaning Universe B was still fine during the day on November 6.
This suggests Vecna’s invasion of Universe B began at night, but Will in Universe A was taken to Universe B by a Demogorgon between 8 and 9 p.m. According to Will’s later recollections, Universe B was already a ravaged, dark world with no living people by then…
Let’s assume Nancy wrote her diary at 6 p.m., and Vecna launched his invasion right after. By 8–9 p.m., when Will arrived in Universe B, everything was already over…
If Universe A and Universe B’s timelines are synchronized, Vecna’s destruction of Universe B’s Hawkins was absurdly fast. In less than 2–3 hours, or even less, he killed every living person in Universe B’s Hawkins, covered the city in vines, and left no bodies behind…
This is completely different from the invasion of Universe A in Season 4. In the Season 4 finale, after Universe A was invaded, it took 2–3 days for the Upside Down’s dark matter to slowly encroach on Hawkins, a significantly slower pace.
After much thought, I came up with two possible explanations:
First: Vecna was severely injured by the teens’ Molotov cocktails and shotgun attacks, greatly diminishing his power, slowing down his invasion of Universe A significantly.
Second: Vecna didn’t complete the sacrifice of all his victims, as Max was barely alive, so the barrier between Universe A and the Upside Down wasn’t fully broken. In other words, Max’s fragile life is Universe A’s last line of defense.
This plot hole could barely be patched, but I soon realized this theory has another massive, unexplainable plot hole:
In Season 1, how did Will communicate with Joyce through the Christmas lights?
Since human activity in Universe B stopped on November 6, 1983,Will shouldn’t have been able to see the Christmas lights Joyce hung up after November 6 in Universe B, let alone the letters written beneath them.
This left me utterly baffled…
I asked a lot of people, and someone told me that there’s an official Stranger Things comic that details Will’s experiences in the Upside Down. It was my first time hearing about an official Stranger Things comic, and I was thrilled, so I rushed to read the comic, only to be utterly shocked…
You see, this is the official answer. The panels show what Will experienced in the Upside Down when he and Joyce communicated via the Christmas lights in Season 1.
At the time, Will was struggling, unsure how to communicate with his mom, and in the next second, the words Joyce wrote on the Rightside Up’s wall magically appeared on the Upside Down’s wall…
WHAT HECK IS THE LOGIC BEHIND THIS????
Then Will traced the letters on the wall with his hand, successfully lighting up the Christmas lights Joyce hung in the other world…
By the way, here’s a key detail not shown in the TV series:
According to the comic, Will wasn’t dragged through a gate to the Upside Down like Vecna was. Instead, like in anime Re:Zero, he travelled to the upside down in the blink of an eye…
Regarding how Will and Joyce communicated via the Christmas lights, this darn comic not only failed to answer my questions but raised even more…
Why did the words Joyce wrote in the Rightside Up appear in the Upside Down? And they appeared out of nowhere…
Can anything other than electrical devices directly cause physical interactions between the Rightside Up and the Upside Down?
Why didn’t anyone else in the group ever experience the physical changes Will saw?
I couldn’t help but feel an urge to strangle the comic writer and the Duffer Brothers…
I patched one hole, only for new ones to appear. The more I thought about it, the more flaws I found.
In the end, I despairingly realized that the Multiverse Theory, which I’d been refining since Season 1 aired, might not be the correct answer.
Honestly, the sense of defeat was overwhelming…
But at this point, I had no choice but to take a new approach and start building a completely new theory.
After a long mental struggle, I developed a second theory: the Universe Overlap Theory.
(2) Universe Overlap Theory, Credibility: ★★★★★
This theory is relatively simpler. Imagine the Rightside Up as a sheet of paper filled with neatly written information.The information on this paper is very organized, including the geography of Earth and the cities built by humans in our world.
The Upside Down, on the other hand, is like carbon copy paper. Compared to the orderly information on the Rightside Up’s paper, this copy paper is scribbled with chaotic, primitive information, utterly disorganized.
When the gate was first opened in November 1979, the primordial Upside Down that Vecna was sent to was the initial state of this copy paper—dark, chaotic, and devoid of human civilization.
At that time, the two worlds looked vastly different because when Eleven first opened the gate, they were very far apart and didn’t affect each other.
In 1983, when Will crossed into the Upside Down, the two previously distant worlds collided and overlapped.
You can think of it as two sheets of paper being stacked together, with the Upside Down’s copy paper being imprinted with some of the information from the Rightside Up’s paper.
As a result, the Upside Down took on the appearance of Will’s Hawkins. In other words, the closer the two worlds are, the more the Upside Down resembles the Rightside Up.
And Will is the one who caused the two Universes to overlap, which might explain why Vecna is so interested in him.
You see, Vecna was also forcibly sent to the Upside Down by Eleven, but his crossing was just a personal journey and didn’t cause the two worlds to overlap.
Imagine Vecna as a tiny drop of ink on the Rightside Up’s paper. Eleven’s powers merely peeled this drop off and flicked it onto the Upside Down’s paper with a splat.
Eleven and Vecna can open a gate between the two worlds, allowing matter to pass between them—like a few drops of ink moving between the two sheets—but that’s it.
Will, however, can directly cause the two worlds to overlap, making the two sheets stick together and imprinting the Rightside Up’s appearance onto the Upside Down.
What a terrifying ability… Vecna must be very interested in it, and this explains a lot of things.
The overlap happened on November 6, 1983, when Will crossed over, so the Upside Down was imprinted with Hawkins’ appearance from that day. Nancy’s diary also stopped on that day.
In Season 2, Vecna kept trying to control Will, likely wanting to use Will’s unique ability to overlap worlds to quickly achieve his goal of invading the Rightside Up.
Think about it: Will was the first person to observe the dark version of Hawkins in the Upside Down. Before him, neither Eleven nor Vecna saw the Upside Down as Hawkins, further proving that Will is the one who transformed it into dark Hawkins.
When Will was trapped alone in the Upside Down, when he was in his living room, frustrated by his inability to communicate with his mother,his superpower activated again! The two worlds overlapped once more because of him!
The Upside Down took on the Rightside Up’s appearance, causing the words his mother wrote on the Rightside Up’s wall to appear out of nowhere on the Upside Down’s wall!
I guess Will’s ability has some limitations. For example, in the scene where he and his mom communicated via the Christmas lights, he only caused the overlap in his house’s room. Other parts of the Upside Down weren’t affected, so beyond his house, the Upside Down remained as it was on November 6.
After Season 1, Will’s physical body never returned to the Upside Down, so we can infer that the two universes didn’t overlap again in the following years, and the Upside Down stayed frozen on November 6.
Similarly, I think when Will first crossed over, his ability only covered Hawkins, altering a small part of the Upside Down, not copy-pasting the entire Earth from the Rightside Up.
The above is the hypothesis under the World Overlap Theory that Will’s superpower reshaped the Upside Down’s appearance.
However, the World Overlap Theory itself can lead to another hypothesis, which I call the “Interstice Universe Theory.” or alternatively, the “Will's Creation of new Universe Theory.”
Here, we borrow the three-universe hypothesis from the Multiverse Theory but make some adjustments to the setting.
The Rightside Up is Universe A, and the dark, barren chaotic universe where Vecna was sent is Universe X (same as in the first theory).
On November 6, 1983, when Will crossed over, his superpower activated, causing the two universes to overlap.
During the overlapping, between the white Universe A and the black Universe X, a gray middle area was created—a new interstice universe, which we’ll call it as Universe B.
It’s as if Universe A is a large cloud of hydrogen gas, and Universe X is a large cloud of oxygen gas,
Will is like a spark that triggers a hydrogen-oxygen explosion, forming a pool of water.
And this pool of water is Universe B, also known as the Upside Down.
Universe B combines features of both Universe A and Universe X, as it’s the product of their overlap.
Its appearance is that of Universe A’s Hawkins on November 6, 1983, but it’s enveloped and filled with dark matter from Universe X.
When Will was trying to communicate with his mother from his house, his superpower activated, causing Universe A and Universe X to further overlap, and the resulting changes were projected onto the walls of Will’s house in Universe B.
The Upside Down that the protagonists visited in Seasons 1 and 4 is Universe B, but they haven’t yet been to the source of the dark matter, Universe X.
Whether Will copy-pasted Hawkins from Universe A into Universe X or created a new Universe B based on the features of Universe A and Universe X, his extraordinary ability is undeniable, and it’s foreseeable that Will will play a crucial role in Season 5.
However, there’s still one unresolved issue with this theory that I can’t confirm. Who caused the two universes to overlap and created Universe B—Will or Eleven?
When discussing with other fans, a significant number of them believe that Eleven is the creator of Universe B.
In Season 1, when Eleven encountered the Demogorgon during her psychic experiments in Hawkins Lab, her powers went haywire in a panic, causing Universe A and Universe X to overlap, creating Universe B and opening the gate between Universe A and Universe B in the lab. This seems plausible too.
The day Eleven opened the gate and the day Will went missing were the same—November 6, 1983—so both of them could have created Universe B based on Hawkins from that day.
So, I can’t definitively determine who caused it. But personally, I think Will is more likely.
If it was Eleven, why didn’t the two universes overlap when she first opened the gate and sent Vecna to Universe X? Was it a coincidence, or is Eleven simply incapable of doing it?
If it was Eleven, how did Will, who doesn’t have this ability, see the words his mother wrote on the wall?
Although there are still many questions, I personally can’t answer them until Season 5 comes out.
These are the best theories I can come up with so far, and they’ve taken a ton of brainpower…
Even after all this, when Season 5 finally airs, I’ll probably get slapped in the face by the final truth.
Which theory do you think is more credible? Feel free to share your own theories!