Man, I had no clue that Golden Age Clayface
was a master of disguise...
I should really bone up on Golden Age Lore.
Other than the addition of Temple Fugate
aka The Clock King (Batman:TAS version) I can't really think of another villian to add to the list.
Also, this thread has made me want to go back and re-experience The DC Comics universe from Episode 1 forward. Looks like I've got another epic marathon in the works after I finish watching all of Doctor Who.