After failing to immediately figure out a picture puzzle, forgetting her locker combination, and turning in a piss-poor school project, Lisa fears she's losing her brainpower, and things get worse when Grampa Simpson tells Lisa that she may have the Simpson Gene, which has already made Homer, Bart, and Grampa himself dumber with age. Meanwhile, Jasper Beardley uses the Kwik-E-Mart freezers to cryogenically preserve himself, and Apu deals with the situation the only way he knows how -- by making a profit off it.

!!This episode contains examples of:
* BittersweetEnding: Indeed, Lisa is shown that she will not be hindered by the Simpson Gene and will go on to remain the intellectual, thoughtful individual she has been. Bart however, is condemned to suffering the Simpson Gene's effects, even if NegativeContinuity takes hold. Bart even considers the disturbing implications of this, before deciding it doesn't matter and going to compete in a game where the Simpson males ram into each other with pots and pans on their heads.
** FridgeHorror: This episode's revelation that the Simpson men will grow dumb as they grow older means that Bart's hard-assed kindergarten teacher from "Lisa's Sax" was correct when she said that Bart would have no future.
* GettingCrapPastTheRadar: One of the attractions in the Kwik-E-Mart besides Jasper is the "World's Most Offensive Baseball Cap" with a subtitle "Do you dare to read it?" Rod and Tod Flanders read "Show Me Your --" before Flanders covers their eyes and [[LastSecondWordSwap assures them it says "Tie"]].
** The nudity in this episode (see NakedPeopleAreFunny below)
* HarmlessFreezing
* HornyVikings: Jasper is fitted with a typical Viking helmet and shield when repurposed as "Frostillicus"
* HumanPopsicle: Jasper tries this in the freezer, becoming "Frostillicus" in the process. He technically does defrost in the future, but it's only a couple of days or so rather than several years when robot wives are "cheap and efficient".
* NakedPeopleAreFunny: Jasper defrosts and leaves the freezer, spoiling Apu's chance to sell him to the Rich Texan (or at least his head). Following this is a gag where the Kwik-E-Mart is remade into a strip joint called the Nud-E-Mart, complete with Apu and Sanjay naked behind a podium and a bike post outside the entrance.
** Kent Brockman's news report about towel snappings features a bare, yellow butt.
* NegativeContinuity: Lots of it:
** If Bart really is losing his intelligence, how is he clever with pranks and manipulating adults (the ones that are stupid enough to fall for his tricks, like Homer, not the ones who are so bitter and jaded over his antics that they're not fooled anymore, like Mrs. Krabappel and pre-{{Flanderization}} Principal Skinner)? Is this a non-canon episode or a bad case of the writers knowing nothing about continuity (the person who wrote the episode was a newcomer named Ned Goldreyer)? Is Bart really as stupid as his father Homer? And what about Grampa? How is he dumb if the "Curse of the Flying Hellfish" episode showed that he was a competent military leader, and "Lisa's First Word" revealed that he ratted out everyone on a crooked 1950s game show just so he can win himself a house?
** And if all Simpson men are doomed to stupidity, what about Herbert Powell (Homer's half-brother whose biological father is Grampa Simpson)? The only stupid thing Herbert did was let Homer design a car for him, but that can be excused as Herbert never knew he had a half-brother who was an idiot. Other than that, Herbert ran a successful car company and made millions on that baby translator machine (until he [[NoodleIncident inexplicably]] lost everything, as mentioned in "The Changing of the Guardian").
** Add to that a later episode revealing Homer's stupidity was the result of a crayon he enlodged in his brain as a child. When it was removed as an adult, he was even more intelligent than Lisa.
* ShoutOut: During her speech to encourage people to use their minds, Lisa describes the works ''Literature/ToKillAMockingbird'', ''HarrietTheSpy'', and ''Yertle the Turtle'' as great literature.
** Homer, Bart, and Lisa watch a show featuring a montage of buildings exploding and imploding. One of the buildings is a Gothic manor with a gate reading [[EdgarAllanPoe The House of Usher]].
** The eraser pig made with springs and pushpins is a reference to a similar prop in Matt Groening's ''Life in Hell'' comics.
* StockLateralThinkingPuzzle: The brain teaser that sets off the episode is comparable to one as Lisa tries to figure out what the last symbol in a series of six would be. She even notes that the symbols don't appear to be anything like Egyptian hieroglyphics or any characters of the like. At the end, she finds that the symbols are made of the numbers 1-6 fused together with a mirrored image of each number.