I don't know it anyone else has done this, but here you go.
Vecna
medium humanoid (Infected Human) Neutral Evil
AC: 17
HP- 242
Strength- 15
Dexterity- 18
Constitution- 20
Wisdom- 21
intelligence- 22
Charisma- 26
Senses- Blindsight 30 ft, passive perception 14
Languages- Common, Undercoating, Abyssal
Challenge- 22
Damage resistances
Resistance to nonmagical bludgeoning, piercing and slashing.
damage weaknesses-
Weak to fire and lightning damage.
Actions-
Psychic link- Vecna chooses one target within 20 ft of him, that target must make a DC 18 Wisdom saving throw. On a failed save, the target takes 4d12 psychic damage, and half as much on a successful one.
Constrict- Vecna chooses one target he can see, that target must make a DC 18 dexterity saving throw, taking 6d6 bludgeoning damage on a failed save, and half as much on a successful one. This also renders the target prone and grappled until their next turn.
Remote Destruction- Vecna chooses one target he can see, he creates a link into that target's mind, that target is prone during the duration of this spell. The target must make a DC 20 Wisdom saving throw each of their turns, taking 5d12 necrotic damage on a failed save, and half damage, on a successful one. Vecna cannot take any other actions while concentrated on this action action. These effects last until Vecna's concentration is broken, vecna is prone while concentrated on this action.
Legendary action
Summon Help- Vecna has the ability to summon either 1D6 Demodogs, 2 Demogorgons, or 1d8 Demobats, once during battle.
Demogorgon Stranger Things Stat Block coming soon!