The Simpsons Treehouse of Horror XXVII and marathon schedule! The annual Halloween-themed The Simpsons Treehouse of Horror XXVIII episode will air on FOX Sunday, Oct. 22 (8:00-8:30 PM ET/PT) and you can watch a preview below. In the episode, Maggie becomes possessed by an ancient demon, Lisa (Yeardley Smith) discovers a creepy/perfect version of her family in an alternate universe and Homer (Castellaneta) cannibalizes himself.