The name of the purple chameleon/lizard is Randall "Randy" Boggs.
Randall is the secondary antagonist of Monsters, Inc. (The main villain being Henry J. Waternoose, the CEO of the Company) and the supporting protagonist-turned-main antagonist of Monsters University.
He is voiced by Steve Buscemi in the films and some of the video games and by Peter Kelamis in the video games.
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