The Simpsons Se11 Ep04 Treehouse of Horror X

“Treehouse of Horror X” is the fourth episode of Season 11, as well as the tenth “Treehouse of Horror” episode. The episode aired on Halloween (October 31st) of 1999, and would be the last “Treehouse of Horror” special to air either before or on Halloween until season 21′s “Treehouse of Horror XX” in 2009, a full ten years later.