These segments usually involve the family in some horror, science fiction, or supernatural setting and always take place outside the normal continuity of the show.
Between "XI" (2000) to "XIX" (2008) and "XXI" (2010), due to Fox's contract with Major League Baseball's World Series, episodes had originally aired in November.
[2] "XX" (2009) and each Treehouse of Horror episode since "XXII" (2011) has aired in October, with the exception of season 32's "XXXI" (2020), which was originally scheduled for October 18, but was postponed to November 1 due to the 2020 NLCS reaching game 7.
[5][6][7][8] Season 34's "XXXIII" (2022) went back to the earlier notion of having different writers for each segment.
The Twilight Zone has been parodied quite often, and has served as the inspiration for numerous segments.