Hoo boy, this old chestnut. Grant Morrison can shoulder some of the blame for this one and all, although he was just reiterating a theory that's been floating around in comics fandom for decades. Alan Moore and Brian Bolland's The Killing Joke is one of the greatest stories in the Batman canon, with wide-reaching implications for the Bat-Books going on (principally the crippling of Barbara Gordon), whilst also exploring the ongoing relationship between Batman and The Joker. At the start of the book the Dark Knight himself waxes lyrical on how the constant back-and-forth of the Joker breaking out of prison, Batman putting him back in, and so on will only end when one of them kills the over. By the end of the story, The Joker has managed to crack a funny that actually gets Batman laughing as hysterically as him, before the police turn up to drag him away. Or, according to Morrison's interpretation, until Batman strangles him to death, which is why the laughter slowly fades away and the camera pans down to the rain falling on the ground. All set up with that opening scene. Apparently.
Tom Baker is the Comics Editor at WhatCulture! He's heard all the Doctor Who jokes, but not many about Randall and Hopkirk. He also blogs at http://communibearsilostate.wordpress.com/
