Not as drastic of a change, but his clothes are little less festive than usual (for now).

It was business as usual in Gothams underworld, until this clown arrived on the scene. At first, The Joker seemed like a harmless idiot, going around to various Mob Bosses and Crime Lords (including Riddler) asking for money loans. They gave it to him, deciding that if he couldn't pay it back, they would just break his legs or kill him. Of course, when they tried to ask for their money back, many of them turned up dead and facially deformed. Soon it became apparent that he was no harmless fool, having used his loan money to turn the toughest crooks in the city into his personal crime army. By the end, only the Riddler was left to appose him, but the two decided that instead of going to war, they would simply stay out of each others way. Joker, as one would expect, continues to be a thorn in Batmans side.