I would’ve liked more humor in Ledger’s Joker, too, but the nurse’s uniform, and the ‘make a pencil disappear’ trick both qualify.
He threw out a Groucho Marx eyebrow-wag while Batman was beating the everloving crap out of him in the police station. And yes, the nurse’s uniform thing was a twist on Bugs Bunny. It’s not quite the killer joy buzzer, but there was a comedy theme for sure.