Wario Apparition

The Apparition is a popular Super Mario 64-related legend, resembling the head of the popular video game character Wario, most specifically, the version of Wario used in the 1995 edition of Space World.

Many players have reported the Wario Apparition to appear in the zone that leads to the ninth level of the game (Dire Dire Docks), chasing the player down the hall, although from there, many different versions spawn, they all have one thing in common: The Wario Apparition morphing into a deformed version of itself (via mouth, eyes or other facial expressions) while chasing the happy-go-lucky plumber.

A popular theory about the strange manifestion reads as follows:

The Wario Apparition was created from the subconscious wishes to see him in Mario 64 that the shared desired caused him to appear as a horrifying half start in some copies of the game. That image is what its supposed to look like, but those who encountered it ingame can't even describe what it looked like as many suffer from memory loss and stroke-like symptoms. If you suspect you're seeing it ingame its suggested you shut the console off immediately because once you give it power by witnessing it, it gains power to begin manifesting itself in your reality.

However, this theory is yet to be confirmed, and the identity of the cryptid remains unknown.