The episode is a parody of Stephen King's 1986 supernatural horror novel It and its film adaptations, It (2017) and It Chapter Two (2019).

From September 29 to October 9, 2022, a contest was held that allowed viewers in the United States to submit spooky Krusty fan art.

The Losers, consisting of Marge, Comic Book Guy, Carl and Moe, defend Homer, and the bullies run away.

Marge kisses Comic Book Guy, who took credit for a poem that Homer wrote for her earlier.

As they plan how to defeat Krusto, Comic Book Guy arrives with the kids to retrieve Marge.

Writer Cesar Mazariegos pitched an idea to do a parody of It for the annual Treehouse of Horror episode, and the producers wondered why they never did it previously.

To complete the love triangle with Homer and Marge, he considered using Moe before choosing Comic Book Guy, whose character was "selfish and needy", and had him be the one who would die.

[5] King previously appeared as himself in the twelfth season episode "Insane Clown Poppy".

[6] A contest to promote the episode was held by inviting fans to submit art depicting Krusty the Clown as Pennywise.

[11] Tony Sokol of Den of Geek rated the episode 4 out of 5 stars stating: "The Simpsons' 'Treehouse of Horror' episodes are always season highlights, and the extra added clowning is a welcome treat (the official 'Treehouse of Horror: XXXIII' is set to premiere next week).

Written by Cesar Mazariegos, and directed by Steven Dean Moore, 'Not It' is quite scary, at times, and every frame carries both thrills and spills.

The clown motif provides a panorama of ways to make the audience choke on laugher [sic], even before a school bully's intestines get twisted into balloon animals.