The one-eyed green monster voiced by Billy Crystal in Monsters, Inc. is Mike Wazowski. He is a round, green cyclops with two small horns and a fast-talking, sarcastic personality.
Mike works as Sulley’s assistant on the Monsters, Incorporated scare floor, where he manages paperwork, timing, equipment, and the practical details of their scare station. Although Sulley is the celebrated scarer, Mike is his closest friend, roommate, and essential partner. Their friendship drives much of the film’s story when Boo accidentally enters the monster world.
Mike’s full first name is Michael, but “Mike Wazowski” is the canonical name used throughout the franchise. Billy Crystal voices him in the feature films and later animated productions. A frequent mix-up is confusing Mike with Randall Boggs, another greenish character who has multiple eyes and camouflage abilities. Mike is also distinct from Sulley: Mike is small and spherical, while Sulley is the enormous blue-and-purple-spotted scarer.