Herobrine

Herobrine is a mysterious entity that appears in Minecraft. He is the God of the game's, "End Dimension." He can make weak ghostly forms of himself known as Stands. It is unknown if this is Herobrine making a whole new entity, astral projection, or something else.

Backstory
Herobrine was originally a human, who became so obsessed with Minecraft, that he used a Heronomicon to teleport to the Minecraft Dimension and become a Hero.