Personally, I always wanted to make the Belltower fight henchman from Batman '89 a regular Joker henchman. He actually manages to hold his own against Batman, which isn't a big deal in '89 since he's not big on martial arts, but I like the idea that this random guy can inexplicably keep up with Batman.
In my mind he basically never talks, is largely off theme in that he's never laughing and always stoic. He's one of Joker's favorite henchmen and he's one of the first he breaks out and rehires for his squad.