History Recap / TheSimpsonsS21E4TreehouseOfHorrorXX

* WerewolvesAreDogs: The Wolf Man makes dog-like yelping noises as his wife is beating him with a newspaper.
* WholePlotReference: ''Don't Have a Cow, Mankind'' is one to both ''Film/TwentyEightDaysLater'' and ''Film/ChildrenOfMen''

* OffWithHisHead: After Homer attempts to sway the anger of the Monsters' angry wives in the ColdOpening, he's promptly attacked and beheaded. His head lands in the bowl of punch with WingdingEyes providing the "XX" of the episode title.

* RoaringRampageOfRevenge: Lisa tries to kill Bart to stop his torment and murders. She succeeds.

* TheSecretOfLongPorkPies: Moe's beer becomes more popular after it gets mixed with Homer's blood.

* ImAHumanitarian: The special ingredient to Moe's brew being Homer's blood. [[LampshadeHanging Lampshaded]] in the lyrics
--> '''Lenny''': Full-bodied!
--> '''Carl''': Full-blooded!
--> '''Barney''': It's such a lovely blend!
--> '''All Three''': It's jolly! It's loyal! Like drinking your best friend!

* ComicallyMissingThePoint: When Kent Brockman becomes the first Muncher, he takes a big bite out of Krusty's arm. The clown angrily shouts "Hey! That's my check-cashing arm, you stupid-!" before becoming a Muncher himself.

* TooDumbToLive: Homer as usual. During "Don't Have a Cow, Mankind", he tells Bart to remain quiet when they attempt to escape. Unfortunately, he then yells "Man, that breeze feels good!", drawing the attention of the Munchers in range. He later is zombified himself when he desecrates what he believes to be the lifeless corpse of his boss, not knowing Mr. Burns is also a Muncher.

* ThheatrePhantom: Barney is shown on a boat emerging from the mist at Moe's bar. He is dressed up like the Phantom from Creator/AndrewLloydWebber's 1986 musical and sings about how Moe's beer is great.

* BaitAndSwitch: In "Don't Have a Cow, Mankind," the zombie apocalypse survivors want to kill and eat Bart to gain his immunity, but Marge argues that there has to be another way. The ending cuts to a saddened Lisa looking around the Safe Zone, now a peaceful place where happy children play, as her monologue in voice-over explains what they had to do to make this happen...let Bart bathe in the community cooking pot. (Which he's gleefully doing as she "speaks.")

* EnfantTerrible: The first segment's iteration of Bart is a 10-year-old psychopath who remorselessly beheads two members of the school's faculty and attempts to induce his sister to kill Mrs. Krabappel. Other than that he remains completely in-character, PingPongNaivete and all (while explaining to Lisa that his apparent references to pranks are [[DeadlyEuphemism Deadly Euphemisms]], he says that it's like how "Mom and Dad say 'snuggle' when what they really mean is 'let's lock the door and hug'").

-->'''Bart:''' A deal's a deal, little sister. Tomorrow after school, go to her house and TP her.

* TooDumbToLive: Homer as usual. During "Don't Have a Cow, Mankind", he tells Bart to remain quiet when they attempt to escape. Unfortunately, he then yells "Man, that breeze feels good!", drawing the attention of the Munchers in range.

* AnalogyBackfire: The residents of the SafeZone's first idea for making use of Bart's immunity is to cannibalize him, causing Marge to exclaim, "What kind of civilized people eat the body and blood of their savior?" Cue Reverend Lovejoy tugging his collar.

* AluminumChristmasTrees: Cows being fed other cows that causes a disease really has happened. The show even calls it "Mad Cow", in referenced to mad cow disease. This happens when a cow is being fed a meat-and-bone meal mixed with their grain, often from remains of other cows. There is still 4 cases every year of mad cow disease. 14,562 cases happened in 1995, mainly in the United Kingdom. However, instead of turning into zombies (or munchers), it affects the brain causing loss of brain function and mobility. It can take months before showing signs and most people die within the first year.

* HeroicSacrifice: Subverted. When the trunk gets stuck on the top of a mound of garbage, Apu volunteers to get out and push the car unstuck with the munchers close in pursuit. He succeeds, but the Simpsons drive off without him, believing he was sacrificing himself to save them when he actually wanted them to park at the bottom of the mound and wait for him.

** Slightly justified in that, just like in the source material, they aren't technically undead, just diseased and cannibalistic.