The Simpsons
Being one of the longest running cartoon sitcoms , there have been instances where the show has undergone changes that could be considered Cerebus Retcons.- Parodied in "Behind the Laughter", the outside-of-canon Animated Actors episode in which we're told that Homer became addicted to painkillers after falling down Springfield Gorge (in a well-known early episode), and that that enabled him to do "the bone-cracking physical comedy that made him a star." There is also, in the same episode, Homer feeding Lisa and Bart growth stunters via executive order in order to keep them looking the same age for the show to explain them never aging.
- In "Hurricane Neddy", Ned Flanders suffers a mental breakdown that leads to him furiously chewing out practically every Springfield resident, after which he voluntarily checks himself into a mental hospital, where he is reunited with his old child psychiatrist Dr. Foster. Dr. Foster explains that as a child, Ned was very hyperactive and aggressive, not helped at all by his beatnik parents who didn't believe in disciplining him. So Dr. Foster performed a long-term series of spankings on him. It stopped his hyperactivity, but it made him practically incapable of expressing any anger, and whenever he did feel angry, he'd instead going into strings of "nonsensical jabbering", namely his verbal tics like "diddly".
- In the episode "Eternal Moonshine of the Simpson Mind", Homer has his life flash before his eyes. The dysfunctional character that we have come to know and love is shown to have a pretty poor time growing up, which makes the dark humor in the show harder to swallow.
- The episodes "Mona Leaves-a" and "Forgive and Regret" show that Homer became the perpetually ravenous Big Eater we've seen throughout the series to cope with the Parental Neglect, and eventual Parental Abandonment, of his mom Mona.Homer: You left a hole in my heart that could never be filled, so I filled it with food, but I'm never full.
- It may have been implied in the past; but the Season 27 episode "Puffless" reveals that Patty and Selma's father died of lung cancer when they were young. This makes his appearance in the Season 2 episode "The Way We Was" (where he is shown smoking a cigar and declaring that Marge meeting Homer "took years off his life") and subsequent mentions after that far less amusing.
- Eleanor Abernathy aka "the Crazy Cat Lady" was first introduced in Season 9's "Girly Edition", as Lisa was trying to compete with Bart's sappy human interest stories. In Season 18's "Springfield Up", we see her early life. At age 8, she was a bright student who was already aspiring to be both a doctor and a lawyer, and by age 24, got her degrees for both fields. But by age 32, she was already beginning to feel burned out, and began drinking and acquired her first cat, giggling a little maniacally at that point. Skipping ahead to age 40, we see that she's become the broken/disheveled cat lady shrieking and wailing incomprehensibly.
- The Season 22 episode "Moms I'd Like to Forget" has a flashback scene where Clancy Wiggum is holding baby Ralph in his arms, then accidentally drops him on his head. Clancy quickly picks the baby up, but notices that Ralph's head has been slightly deformed, and his mannerisms have changed. So it is strongly implied here that Chief Wiggum's clumsiness is the reason for his son's quirks and mental deficiencies.
- For most of the show's run, Bart was the fun-seeking troublemaker we know and love him as mostly for the fun of it. Later on, if the ninth season episode "Lisa's Sax" is anything to go by, Bart became the fun-seeking troublemaker he is now because of the Sadist Teacher running his kindergarten class, and that his parents (especially Homer) Gave Up Too Soon on getting him the therapeutic help he needed no thanks to the aforementioned Sadist Teacher.
- "Who Shot Mr. Burns?" has Homer hitting a Rage Breaking Point with the Running Gag of Burns never remembering his name, just in time to provide his prime motive as a suspect in the shooting. Previous episodes had never once hinted that it bothered him, and it retreats into the background again once the Darker and Edgier two-parter is over.
- This has sometimes been applied to the Running Gag of Homer cartoonishly strangling Bart, which was typically Played for Laughs with the occasional touch of Black Comedy. "Grampa Vs. Sexual Inadequacy" implies that Abe did the same thing to Homer growing up (according to "A Father's Watch," it goes back a bit), while The Movie turns the joke into an outright Tear Jerker by showing that Bart expects this treatment to a degree that he gets right into position upon making a mistake and is then taken aback when Ned Flanders doesn't strangle him.
- Season 24's "The Saga of Carl" reveals that Carl Carlson, a longtime friend of Homer and half of a Those Two Guys relationship with Lenny, never actually saw either as his friends due to their lack of inquiry into his life. If you thought he and Lenny were Heterosexual Life-Partners at minimum, poor Lenny's just as shocked as you are.
