Henry J. Waternoose, or simply known as Mr. Waternoose or Waternoose, is the hidden main antagonist of Monsters, Inc. He is the former CEO of the company and Sulley and Mike's former boss who was driven to villainy out of his own desire to keep his company running. He at first appears to be a mentor, father figure, and good friend of theirs, but in actuality he is the true mastermind behind the plot to kidnap Boo and use the scream extractor on her and Randall (the character who at first appears to be the main antagonist) was actually working for him all along.
- Waternoose's first and middle names are never spoken in the film.
- Kelsey Grammer was offered to play Waternoose in Monsters University but he turned it down.
- It is never revealed what his middle initial J. stands for but many assume it means James.