At the start of Pixar’s Monsters, Inc., Sulley works as a scarer.
A scarer enters a child’s bedroom through a special door and frightens the child, producing screams that the company collects as an energy source. Sulley is the factory’s leading performer in this role, and his reputation drives the opening workplace competition with Randall.
The job is presented like a demanding professional occupation, complete with performance records, co-workers, supervisors, and safety rules. Sulley’s success comes from his imposing appearance and experience, but the arrival of Boo challenges his assumptions about human children and the purpose of his work.
Sulley later helps expose the factory’s harmful practices and supports a new system based on children’s laughter. Thus, “scarer” describes his initial occupation, not his eventual role in the company’s reformed operation.