Basil Karlo as Clayface

Basil Karlo was an actor who upon discovering that a remake of one of his classic horror movies was being made went insane and began killing the cast and crew, wearing the mask of the film's villain Clayface, until stopped by Batman. Initially having no superpowers, Karlo joined with a group of other "Clayfaces" and stole their combined powers, allowing him to shapeshift into any forms he wants. (1)