Which Pixar character is voiced by Frank Oz in Monsters, Inc.?

Frank Oz voices Jeff Fungus in Monsters, Inc.

Jeff Fungus is Randall Boggs’s assistant at Monsters, Incorporated. He is a small red monster who is repeatedly pulled into Randall’s schemes, including the work surrounding the experimental scream-extraction machine.

Frank Oz is widely known for performing several characters in The Muppet Show and Sesame Street, especially Fozzie Bear, Miss Piggy, and Grover. His brief voice role in Monsters, Inc. is therefore an easy credit to overlook, particularly because the film features a large ensemble of monster characters.

Jeff Fungus is sometimes confused with other minor employees, including Smitty and Needleman, who are associated with maintenance work at the company. Randall Boggs himself is voiced by Steve Buscemi. The question refers to the original English cast, not a dubbed version in another language.