Dahmer. I got a neat back story for that already: First, he eats his parents after they were shot (and embaulmed), and that's when he develops an insatiable hunger.
Quote:
Joker teams up with Charles Manson, then gives up after five minutes, saying "Boy, Manson is really fucked up!"
I think that made me laugh for three full minutes.
Charles Schultz's Peanuts is parodied by the JLA (I don't think it'll take too much brainstorming to figure out who Charlie Brown'll be).