Treehouse of Horror XI Treehouse of Horror XI “Hmm, Bottlenose bruises. Blowhole burns. Flipper prints. This looks like the work of rowdy teens. Lou, cancel the prom.” Chief Wiggum[src] "Treehouse of Horror XI" is the first episode of Season 12. This is the first Treehouse of Horror episode to air in November. This is also the first Treehouse of Horror episode to air in the 2000s (also originally going to be an episode for the eleventh season in production order) 1 Synopsis 2 Full Story 2.1 ...