Twenty-five years on from being released, Monsters Inc remains one of Pixar’s greatest films.
However, a fan theory suggests the animated comedy has a far darker undertone riding beneath the surface.
The 2001 film follows Mike Wazowski (Billy Crystal) and James ‘Sulley’ Sullivan (John Goodman), two best friends turned employees at a factory that produces energy in the world of Monstropolis.
To do this, they have to scare children, whom they believe to be toxic, and this leads to chaos when young girl Boo finds her way into Monstropolis.
Mere moments into Monsters Inc, an advert for the company the pair work at is shown on television, and viewers can hear the ad state that each monster is carefully matched to every child to produce superior screams “refined into clean, dependable energy”.
This led one Reddit user, named curlyquirkycolourful, to ask a pertinent question: if “clean energy” exists in Monstropolis, and this is being highlighted in the company’s commercials, then this suggests they once harvested a form of energy considered dirtier, and one that now appears to be considered unacceptable to use.
The theory suggests that the energy the monsters of Monstropolis have moved away from could be something more ominous; maybe instead of making children jump to get their screams, perhaps they previously inflicted pain – or even drew blood.
“Since we categorise the forms of energy we use, this ranking would equate to their world as well,” the post reads.
The film’s writers, Andrew Stanton and Daniel Gerson, and director Pete Docter have never commented on this theory, but it’s certainly an unanswered question within the Monsters Inc world.
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A prequel to Monsters Inc, titled Monsters University, was released in 2013, and TV sequel Monsters at Work followed in 2021, with both Crystal and Goodman reprising their roles.
Speaking about opting to do a prequel film over a sequel, Docter told EW: “We purposely did that because we didn’t want to answer some of the questions about what happens to Boo – how does she grow up, and things like that. It would have to be really compelling, which is hopefully the benchmark for all of our sequels, anyway.”
He also revealed that Crystal’s Mike ”was not in the first draft”, adding: “Our first movie was about Sulley and this kid, and then in subsequent story note sessions, we thought it would be nice for Sulley to have a little bit more of a backstory and a world that gets upset.”
The latest Pixar film to have been released is Toy Story 5, which has become the highest-grossing film of 2026 to date.
