23rd Oct: It's time for the second TV Tropes Halloween Avatar Contest, theme: cute monsters! Details and voting here.
Finn and Jake come across village after village where all the gold has been stolen by a mysterious monster called The Gut Grinder. And each village presents more evidence that The Gut Grinder looks so much like huge!Jake, Jake must be him! Eventually Jake starts doubting himself, and when in the Spike village he gets thrown in jail, decides that it must be true. Meanwhile Finn finds one last bit of gold, which attracts the real Gut Grinder (who is not Jake). Jake, who has gone crazy, breaks out of jail and fights the Gut Grinder... then snatches the gold for himself and runs away. Finn tries to remind him who he is, but fails. Sad, he takes Jake's viola and starts playing. Badly. Jake abhors this sound so much that he returns to take his viola back, in the process remembering who he really is. And the Gut Grinder turns out to be a Spike woman in a suit made after Jake because she thinks he's hot.