South Park has had several severe Flanderizations. In general, it quickly evolved from an irreverent adult show about kids to a biting political satire, with the adults taking as important a role as the kids. Season 12 is considered a particular turning point, marking Bill Hader's introduction to the writing team; nearly every episode became political and extremely topical, and yet somehow targeted more toward teenagers. The political element is reflected in some characters' Flanderizations as they start to voice different political viewpoints: Stan became the moderate liberal, Kyle became the moderate conservative, Wendy became the hard-left militant feminist, and Cartman became the alt-right Politically Incorrect Villain. It should be noted that some view some of these shifts in characterization as meaningful Character Development, especially as some episodes focus on their struggles spurred by these changes, while others view them as character assassination or blatant Characterization Marches On.
- Stan started out as the Only Sane Man, but still childlike and mean-spirited (compare his treatment of Butters between early and late seasons). Then his maturity and intelligence were exaggerated to the point that he outclasses most of the adults, but he also became bitter and cynical, griping at everything around him so much that fans are sharply divided on whether to agree with him. He's also become more wangsty and impulsive, looking disturbingly like his father Randy, which comes to a head in "Post Covid", which shows that he became a Future Loser as an adult (mirroring Randy) who grew to resent everything about South Park (though he has a Heel Realization later on).
- Kyle went from being the voice of reason and a contrast to Cartman's impulsive nastiness to a much more prudish, stuck-up know-it-all (oftentimes even being described as such in-universe) defined by his rivalry with Cartman. He also became a Butt-Monkey, almost to Butters' level, which as Season 21 shows, can cause him to double down on his soapboxes even more, to the point of being able to commit his own atrocities and justify them (again, just like Cartman). Like Stan, this reaches its peak in "Post Covid", where he's unable to be happy as an adult only because he keeps comparing himself to Cartman's Ridiculously Successful Future Self, whom he still accuses of being a Bitch in Sheep's Clothing.
- Cartman is an interesting case, as his Flanderization into a cartoonish villain led to his becoming a much more competent and cunning character than how he started out. He began as a selfish, impulsive kid who could never think beyond his momentary desires, but became The Chessmaster whose evil was entirely premeditated. He began as a whiny brat who could only sway his mother, but became a master manipulator who can play huge crowds like a fiddle. He began as Kyle's friend (well, in the sense that he's The Friend Nobody Likes) and became his mortal enemy. He began as a mild anti-Semite, making fun of Kyle for not celebrating Christmas just to get a rise out of him, but became a full-on neo-Nazi who admires Hitler and tries to instigate his own Holocaust. Despite this, and excluding a regression in Season 21, he has become a lot more tame over the years, having more Pet the Dog moments and failures, to the point where many of his plans backfire on himself. Notably, his anti-Semitism has also been downplayed and now only pops up when Cartman benefits from it (though this also likely has more to do with having PC Principal as an authority figure).
- Kenny’s perverted tendencies have also been upped, turning him from a mild Covert Pervert who was slightly more knowledgeable about sex than the other boys to a hedonistic Dirty Kid who collects mountains of porn and tries to have sex with women whenever he can. Kenny's an interesting case, considering that besides that, he might be the one who went through the most Character Development otherwise. Also, his interest in sex has been toned down or not focused on as much over time.
- Wendy Testaburger started out as little more than a prepubescent Hello Nurse character who had who had a mild rivalry with Cartman and who shared Puppy Love with Stan, which is the main focus of his character arc in The Movie. Very early on, she became extremely possessive of him, while he became more aloof. After a Breakup Makeup Scenario that lasted from Season 7 to Season 11 (though it was only the focus of three episodes), Wendy became more demure herself in regards to Stan, though she became more active in everything else, occasionally outwitting and even bruising Cartman at his own games. However, she also became a Soapbox Sadie, as the writers used her as a mouthpiece for their harder left-wing viewpoints, with her relationship with Stan becoming a secondary trait to her. This proved to be relatively detrimental for her since viewers were split on whether or not they agreed with her takes on subjects.
- Butters started out as just one of the many "weird" kids. He became an Unpopular Popular Character with occasional moments of brilliance, but whose naiveté could get the better of him (which characters like Cartman were quick to exploit). After years of being around Cartman, he became the show's most extreme Butt-Monkey whom everyone took advantage of (compare how hard it was for the boys to manipulate him in Season 6's "Freak Strike" and how easy it was in Season 14's "The Tale of Scrottie McBoogerballs"), to the point where he could be easily guided into accepting blame for an action he didn't commit, and in particular picked up a Hilariously Abusive Childhood, as his parents were established as abusers who seem to punish Butters for merely existing. Though they eventually Took a Level in Kindness after Season 8, Butters had the opposite problem, and became more prone to having violent outbursts or participating in shady activities with or without Cartman (compare how he deals with Lexus' rejection in "Raisins" to how he deals with Charlotte's breakup in "Weiners Out!"), with Season 20 being a particular low point for him, turning him into a Mirror Character for Cartman while Cartman himself was trying to undergo a Heel–Face Turn.
- Stan's father Randy started out as one of the smartest characters on the show, but with a "wild side" and an inability to catch up to fads or pop culture, both born out of his desire to connect with his son. As Stan became smarter, however, he became dumber, and by Season 8, he was a Knight Templar Parent who would spearhead the other parents' hysteria of the episode, before becoming a hyperactive, paranoid, and idiotic Manchild (which interestingly is some fans' favorite version of the character). He only got worse after buying Tegridy Farms, whereupon all of his negative traits worsened, such as his selfishness, cowardice, tendency to overreact and railroad his family into going along with his hare-brained schemes, and other Jerkass tendencies, while jettisoning his love for his family and other positive traits, turning him into an emotionally abusive, sociopathic Corrupt Corporate Executive who would do anything to keep his hold on the town’s weed monopoly and is willing to murder people to weasel his way out of bad situations, and whom everyone in town (including his family) hated. Though he had a Heel Realization late in Season 25, and seemed to go back into a Jerk with a Heart of Gold by the next season, he's still prone to backpedaling whenever there's weed or money around, and he's still a Base-Breaking Character both in and out of universe. His Flanderization in season 23 is Lampshaded in the song “We missed you, Randy”, which plays during his Heel–Face Turn.We missed you, Randy. Where did you go?
It’s like you just became a one-note, overwrought, part of the show~ - Mr. Garrison started off as a troubled and loud-mouthed bigot who always spoke his mind, but who occasionally could still show a softer side around the kids. After running for president and winning, he became a Trumplica who had all his racist traits cranked to eleven, to the point of surpassing even Cartman in terms of Comedic Sociopathy. After losing his next election, he went back to being a teacher, and started a relationship with a man named Rick, with whom he tries to change for the better, with Season 26's "Spring Break" lampshading his character change by having him try and fail to avoid regressing into his "Trump" characterization while on vacation in South Carolina, which the show treats almost akin to kicking a drug habit. In that very same episode, the show hints at Garrison possibly "relapsing" again were Donald Trump to win the 2024 elections.Garrison: Oh, Rick. I don't want to go through all that again, I just wanna stay in South Park with you!
Rick: Well, guess we'll just have to see what happens. - Mr. Mackey was originally a demure Extreme Doormat who never raised his voice against the kids or anybody else, and who was polite to a fault. After becoming a more central character, some episodes like "Mystery of the Urinal Deuce" began giving him Berserk Buttons that caused him to act uncharacteristically mean when pushed, but these only got worse and more petty as the show progressed, to the point of almost having a Sugar-and-Ice Personality. In Season 24's "Vaccination Special", he's abrasive towards the boys without hardly any prompting (granted, it was because he was frustrated over the pandemic, but still).
- The show's fastest Flanderization happened in season 20 to the newly-introduced Member Berries, talking sentient fruits whose original gimmick was making people reminisce about the past by reciting innocuous (and some not-so-innocuous) pop culture trivia from The '80s. It took only a couple of episodes for them to be Flanderized into exclusively referencing Star Wars (possibly as a lead-up to the joke about bringing back "the real Stormtroopers"), before their plot line was abruptly dropped. Though they returned to their original gimmick in "The Fractured But Whole", by then they were completely Out of Focus.
