The Irresistible Lure of the Joker
The Joker's hair is green. It's always been green. But when James Holmes was taken into custody after the Aurora murders on July 20, New York City's police commissioner announced that Holmes had painted his hair red (he may have meant the bright orange-red shade that's appeared in recent photos) and that Holmes had been saying he was the Joker. It's a mark of the reflexive, thrilled horror with which pop-culture audiences regard the Joker that ordinarily reliable news outlets reported those two claims together without questioning them and might have done so even if the movie at which the massacre happened had been Magic Mike.
The Joker doesn't even appear in The Dark Knight Rises, but his specter hangs over more than 70 years' worth of Batman stories. Created by artist Jerry Robinson with Bill Finger and Bob Kane in 1940, he's been Batman's opposite number since the beginning. He spent a while as a goofy prankster in the comics of the '60s, the era when Cesar Romero played him on Adam West's Batman ABC show, before being rehabilitated to his original characterization as a homicidal maniac in the early '70s. Heath Ledger's Joker in The Dark Knight is the signature role of Christopher Nolan's trilogy, the performance that made the movie crackle with terror. (Today, the people who dress up as the Joker at comics conventions almost always replicate Ledger's version, the "Nurse Joker" outfit being a popular variant.)
So what's so compelling about the Joker as a character? It may be that he's the ungovernable force of horrific violence. Almost all of Batman's adversaries are deranged fetishists of one kind or another. They're fixated on money or vengeance, compulsively acting out their obsessions with dualities or riddles or umbrellas. All of that suggests that Batman is mad, too, although his fetish takes a socially beneficial form: dressing up like a giant bat to terrify criminals, especially those who dare to use a gun.
The Joker, though, is just deranged. He has no master plan, no grand scheme -- not even any particular desires, other than to be a wild card that, as Michael Caine's Alfred muses, just wants to watch the world burn. That makes him a terrifically compelling antagonist, because his sole objective is to frustrate everyone else's objectives. It also means he's no kind of protagonist, not even an antihero. (It's telling that when DC gave the Joker his own comic book series in 1975, it only lasted nine issues.)
Every other character in superhero stories has an origin story, an explanation for how they became what they are. The Joker doesn't, not really -- Alan Moore and Brian Bolland took a stab at it with 1988's The Killing Joke, though they suggested that even that might be a false memory -- and that blank slate makes him a perfect vessel for the lost. Even Batman can pull off his cowl and pretend to be Bruce Wayne, but the Joker's face isn't a mask: He's always and forever an evil clown, one who can never take his makeup off or break character. His is the inexplicable cruelty of someone who not only does terrible things, he finds them amusing.
Douglas Wolk is the award-winning author of Reading Comics: How Graphic Novels Work and What They Mean