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THE SIMPSONS · SEASON 21 · EPISODE 4

The Simpsons S21E04 Treehouse of Horror XX

★ 8.4 · GREAT Oct 18, 2009 30 MIN FOX
Still from The Simpsons S21E04: Treehouse of Horror XX

The episode in brief

In the 20th anniversary of THE SIMPSONS annual "Treehouse of Horror" Halloween special, three chilling tales of Halloween horror unwind. First, Lisa becomes livid with Miss Hoover, and in a series of homages to classic Hitchcock sets out for deadly revenge. Next, Krusty's latest fast-food sandwich transforms news anchor Kent Brockman into an enraged zombie and twenty-eight days later, cannibal zombies have overrun Springfield. In the final frightening fable, Homer accidentally falls through a trapdoor in Moe's tavern and impales himself on the pipes of Moe's microbrewery. Moe serves the barflies a glass of delicious beer flavored with Homer's blood and Homer, now half-man, half-brewing apparatus, returns for vengeance.

FAN DESK VERDICT A top-shelf entry. Not quite canon, but you’ll be quoting it all week — the fan desk says don’t skip.

Who’s in it

SERIES REGULARS

Where it sits in the season

TAP A BAR TO JUMP

Where to watch S21E04

US · NOVEMBER 2026
AVAILABILITY IS FOR THE SHOW; NOT EVERY SERVICE CARRIES EVERY EPISODE · LINKS MAY EARN US POPCORN MONEY
8.4
THE FAN VERDICT
Keeper. Goes straight in the rewatch rotation.

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S21E04 FAQ

When did The Simpsons S21E04 air?

The Simpsons S21E04 (“Treehouse of Horror XX”) first aired on October 18, 2009.

Where can I watch The Simpsons S21E04?

In the US, The Simpsons season 21 — including this episode — is available on FX, Hulu, Disney+, fuboTV, DirecTV On Demand, Spectrum On Demand, YouTube TV, FOX One Amazon Channel, Hulu on Disney+, Amazon, Fandango at Home, and AppleTV.

Is The Simpsons S21E04 a good episode?

Fans rate The Simpsons S21E04 (“Treehouse of Horror XX”) 8.4/10, which puts it in the great tier for The Simpsons.