Henry J. Waternoose III, also known as Mr. Waternoose or simply Waternoose, is the hidden main antagonist of Monsters, Inc. He is the former chairman of the company, Sulley and Mike's former boss, mentor, best friend, and father figure, and Randall's former boss.
He was voiced by the late James Coburn.
- Waternoose used to like Sulley and Mike as friends and believed Sulley to be his Top Scarer. He will also do anything to keep Monsters Inc. up and running.
After Mike explains Randall's plan to him, Waternoose agrees to help return Boo to her door; but after Mike tells him he got the wrong door, Waternoose says that he knows and that the door is for Sulley and Mike, thus revealing that he is the one behind Randall's plan and that Randall is working for him. Then he proceeds to push them into the door and banish them in the Himalayas. From that day on, Sulley, Mike, and Waternoose have now been enemies. He planned to kidnap thousands of children and extract their screams to keep Monsters Inc afloat. Fortunately Sulley and Mike were able to rescue Boo and get Waternoose arrested before he could hurt Boo and many other children. It is quite possible Waternoose regrets his actions when he hears about the company's new rebounds in prison.
Waternoose is a gray obese crab/spider-like monster with six legs, five eyes, and two hands with 7 claw-like fingers on each one. He wears a black tuxedo jacket and bow tie, a white shirt, and a red vest with four gold buttons.
- Because Waternoose said "I never should've trusted you with this" to Randall, Waternoose is often thought to be Randall's henchman however this is not true. Waternoose was in no way stating that he was following any kind of plan of Randall's what so ever as what he really meant was that he regrets assigning Randall the task of aiding him in his scheme which especially makes the most sense since Waternoose was the CEO of Monsters Inc and as CEO he holds authority over all workers of the company (Including Randall). Scenes that prove that Waternoose is the one who's really pulling the strings include...
- After Sulley saves Boo from The Scream Extractor shortly after he says that Waternoose is shown ordering Randall to stop them from escaping displaying that he's the one who holds the authority.
- During the scene where Mike is trying to explain everything to Celia as he, Sulley and Boo are being pursued by Randall at one point he says "Waternoose had this secret plot" specifically sating that the whole thing was Waternoose's idea not Randall's.
- His middle name J. is sometimes thought to stand for James. However, this is currently unconfirmed.
- Waternoose is sometimes thought to have been the founder of Monsters, Inc. However, this is false information as he even said so himself that Monsters Inc had been in his family for three generations.
- He is a cross between a crab and a spider.