"Treehouse of Horror XXIX" is the fourth episode of and the 643rd episode overall. It originally aired on October 21, 2018. Episode Summary
The episode follows the classic three-segment anthology format, framed by a brief intro where the family participates in a "soul-eating" contest in (a parody of H.P. Lovecraft’s Innsmouth). "Intrusion of the Pod-y Snatchers" [S30E4] Treehouse of Horror XXIX
Cthulhu appears in the intro, having a "contest" with Homer. "Treehouse of Horror XXIX" is the fourth episode
The third segment mirrors the plot beats of the franchise, including the iconic gates and the "chaos theory" warnings. Quick Stats Director: Matthew Faughnan Writer: Joel H. Cohen Lovecraft’s Innsmouth)
A parody of the movie Split . Lisa develops multiple personalities (including a wealthy socialite and a street-smart kid) after a bad reaction to a chemistry experiment. She kidnaps Bart, Nelson, and Milhouse, trapping them in a cell. The segment ends with a twist involving the "placement" of brands and a meta-commentary on the episode's own production. "Geriatric Park"
The opening sequence is heavily inspired by The Shadow Over Innsmouth , featuring Cthulhu.