Randall was a scarer at Monsters Inc., where monsters would frighten children, whose screaming would power the city. However, more and more children started to lose their fear of monsters. At some point in the film, Randall began construction of the "Scream Extractor", a device that would literally suck the screams out of children. The company's CEO, Henry J. Waternoose, agreed to help Randall with his plans if it would solve the energy crisis.
However, a young girl who Sullivan referred to as Boo managed to enter the monster world, and Randall soon discovered that Sullivan and Mike were keeping her. Randall later kidnapped Mike and attempted to use the Scream Extractor on him, however, Sulley and Boo managed to rescue him. The trio then informed Waternoose of Randall's treahcery, but he then revealed he was in league with Randall, and the two took Boo and banished Sulley and Mike to the Himalayas.
With the duo dealt with, Randall and Waternoose attempted to use the Scream Extractor on Boo, but Sulley managed to return to the monster world and destroyed the machine. Furious, Randall attacked Sulley and proved to be a formidable adversary due to his ability to blend into his surroundings. However, after a lengthy confrontation, Boo beat Randall with a baseball bat and allowed Sulley to subdue him. Randall was immediately tossed into the human world, where he was attacked by a hillbilly family and mistook him for an alligator.