The shaggy Sulley (James P. Sullivan) is already known from Monsters, Inc. There, he works alongside his friend Mike and is a master at scaring children. Monsters, Inc. generates energy for the city of Monstropolis from the screams of frightened children. Before Mike and Sulley became true master scarers, they both attended Monsters University. At Monsters University, Sulley and Mike are housed in the same room. This initially means a lot of trouble, as they can't stand each other and are in fierce competition.