Fungus

From Pixar Wiki

Fungus is Randall's best friend, sidekick, and assistant at "Monsters, Inc.". He is a small red monster with three eyes and legs, similar to those of a chicken. He wears three lensed glasses.

Fungus is rather wimpish, due to the wrathful temper of Randall, and helps him with his plot to revolutionize the scaring industry, although he regrets it.

Fungus is initially a kind person and means well, even apologizing to Mike about his capture. After Randall is banished to the human world, Fungus is a lot happier and takes on the job of making children laugh. He is voiced by Frank Oz.