The Chameleon is a master of disguise.
He gives himself away when he is confronted with Worcestershire sauce, which he hates.
The New Scooby and Scrappy Doo Show
He escaped from Wholesome Prison by disguising himself as part of his cell wall with some paint he stole and making it look like he was no longer there, so the guards would open the cell. In trying to steal the gold medals at the World Games he disguised himself as the statue of a discus thrower, Scooby-Doo (even flawlessly imitating his voice), a waiter, and Chairman Lewis. (Scooby's Gold Medal Gambit)