Doors

Doors are a major way of going from room to room in the Monsters, Inc. factory from the movie Monsters, Inc. Scarers use this technology to enter the Human World and scare children. The main plot of the movie is about Mike and Sulley trying to return Boo to her door (shown to the right).

If a door led to a bedroom of the child who's being scared then it's a good door and it gets shipped over the world but If a door led to the bedroom of a child that is unable to be scared, then it is declared "dead" and is immediately destroyed using a shredder, leaving only the doorknobs intact (although it's revealed at the end of the first film that the door's remains can still be put back together and therefore repairing it with time). Doors can also be destroyed if dropped from a great height (such as the one Randall dropped from a conveyor belt in the Door Vault prompting Mike and Sulley to enter it immediately before it is smashed, and the door leading to the Trailer Son and Mom's trailer and hence Randall's defeat, preventing him from returning) or overloaded with an unusually strong scream (such as the door leading to the cabin as a result of Mike and Sulley scaring several human adults).

In Monsters University, due to it being a prequel, all of the doors' stations were much larger, more rectangular, and clunkier in appearance, probably so that they all appear very old and outdated. It should also be noted at all of the doors in the film are made of wood, except for the one for banishing monsters to places in the Human World like the Himalayas, which is made of metal.