I've never played the game Epic Mickey, so I was unaware of this. I guess the clock tower from the facade of the Small World ride has gone insane from hearing that dang song so many times, and must be defeated by Mickey, as shown here by Jason Corlett. That's pretty hilarious - I may just have to get that game if it's got more humor like this.
I know the one above is closer to the still shots I've seen from the game, but I rather like this version, without all of the lighting effects. I'd like to see Jason do a straightforward rendition of the ride as found in the parks.