Disproportionate Retribution / South Park

Cartman's mom: Eric, that was very naughty!
Cartman: Well he called me chubby!

— This conversation took place after Cartman was sent to the principal's office for chaining a little boy's ankle to a flagpole and convincing him to saw off his own leg to escape.

• Eric Cartman is the patron saint of this trope.
  • In "Scott Tenorman Must Die", Scott cheats Cartman out of $16.12, makes him beg for the money back (in a very humiliating fashion), burns the money in front of him, then tapes Cartman begging for his money and shows it to the entire town of South Park. So after more mundane revenge pranks fail, Cartman lures Scott's parents to their deaths, steals the bodies, grinds them up, uses the meat to make chili, then makes Scott eat the chili. He also gets Scott's favorite band to laugh at him as he cries, while Cartman laps the tears up right off his face. Granted, Scott acted really dickish to Cartman, but even so...
    • Scott Tenorman eventually would prove the old Klingon proverb that, yes, revenge is a dish Best Served Cold, though considering what he was put through, that revenge might have been considered proportionate.
  • In "Tsst", Cartman tied a boy's ankle to the flagpole, gave him a hacksaw and told him he had poisoned his milk, and the only way to get the antidote was by hacking off his own leg. The reason for this, you might ask? The boy called Cartman "Chubby".
  • Similarly, in "T.M.I" when a psychiatrist was calling Cartman fat to see what the reaction would be, Cartman's response is for "Mitch Conner" to lie to the psychiatrist's wife that he's been chatting online with an underage girl, which leads her to shoot herself out of fear and shame. That is one fearsome Berserk Button.
  • "Tonsil Trouble": Most people would agree that laughing at someone getting AIDS is definitely a Jerkass move. Unfortunately, this is Kyle who does it and the person provoked is Eric Cartman. Cartman decides to deliberately infect Kyle with AIDS because he laughed at him. This is even more disproportionate when you consider that there was a Running Gag about Cartman laughing at the thought of Kyle getting AIDS.
• In "Douche and Turd", Stan just expresses his opinion about not wanting to vote for either of the two joke candidates for the school's new mascot, and this gets him threatened, kicked out of town, and almost killed, in that order.
• Kyle as well, particularly in recent seasons. Don't read Apple EULA? Have fun being part of a HUMANCENTiPAD. He also gets AIDS from Cartman for laughing at his condition, loses a bet and is forced to suck (at least imagined to) Cartman's balls.
• Butters often faces this from his Abusive Parents, being grounded over looking "silly" in a school photo, having nightmares, allegedly misplacing the Hamburger Helper (which was Stephen's own fault), apparently insulting them (which was actually Cartman's doing), being voted the ugliest boy in his school, escaping from Paris Hilton after being sold to her by them for $250 million, and so on.
• South Park: Bigger, Longer & Uncut had Shiela start a war with Canada over a movie, just because it was responsible for making her children swear.
• In "The List", Kyle attempts to burn down the school because he was listed as the ugliest boy in the school. That said, Cartman and many of the other kids making fun of him for it certantly didn't help.
• Mr. Garrison is good at this too. In "Follow That Egg", whilst he's still a woman, he tries to get Mr. Slave back but fails because Mr. Slave is getting married to Big Gay Al. So instead of just dealing with it like a normal person, he goes out of his way to try and prevent gay marriage from happening and going to insane lengths to prove that gays shouldn't be married. Said insane lengths include trying to have what he calls a fag drag, paired Stan and Kyle together to prove that gays shouldn't be married by having their egg assassinated by a professional assassin, who caused a massacre. So in short, Mr. Garrison is responsible for the deaths of hundreds and nearly killed two of his students all because his ex didn't want him back since the sex change and was getting married to another man.
• In "The Death Camp of Tolerance", Stan, Kyle, Cartman and Butters are all sent to a Schindler's List-style concentration camp by their parents for allegedly being homophobic towards Mr. Garrison, when they were actually just disgusted with Mr. Garrison's inappropriate behavior.
• "Terrance and Phillip: Behind the Blow" involves a group of people who flat-out claim to be the "Earth Day Brainwashing Committee" (like if it works), who accuse the boys of dooming several endangered species and chase around with a cleaver and chop off Kenny's limbs all because Kyle seemed to have lied about having Terrance and Phillip come to the Earth Day Festival, even if the substitute was just as good.
• In "A History Channel Thanksgiving", Kyle sarcastically deduces that the pilgrims were aliens while being interviewed by The History Channel, which angers the partial Native American citizen David Sawitsky and has the boy held at gunpoint at his own house. This comes back on him when an interdimensional Pilgrim soldier mistakes him for a stuffing-raiding Indian villain and brutally kills him.
• In "With Apologies to Jesse Jackson", although Randy saying the n-word (on accident) on national TV was indeed a big deal, it did not justify the things Randy became a victim of (public humiliation, ridicule, and three men trying to kill him), with the latter happening even after he publicly apologised.
• In "The Death of Eric Cartman", the boys pull one on Cartman just because he ate all the chicken skins from their KFC. They decide to ignore him (and encourage all the other students to do so as well), to the point where Cartman believes he died and is now a ghost. This is despite Cartman having done far worse in the past, although it could also have been The Last Straw for the boys.
• "Pandemic". The Department of Homeland Security takes every Peruvian flute band they can find and takes them away to Miami where they plan to make them spend the rest of their lives. Why? For the sole reason that they find them annoying. That is what it seems like, until Part 2, when we find out that the Peruvian flute bands were the key to keeping a horde of monstrous guinea pigs from causing massive destruction. The DHS did that knowing full well what would happen, because the head of the DHS was actually the leader of the guinea pigs in disguise.
• In "1%", Cartman responds to being teased about "crying to his stuffed animals" every time he is persecuted by subconsciously "murdering" his stuffed animals one-by-one, staging the "deaths" to appear as though they the were victims of a Serial Killer out for revenge on Cartman, and burning down his own house. Also known as "Cartman's interpretation of 'growing up.'"
• In the "Imaginationland trilogy", Imaginationland itself is evenly split between the Good Imaginary Characters' territory and the Evil Imaginary Characters' territory. The Evil Characters never allowed anything Good to come into their territory or else the Evil characters would kill them. When the terrorist cell attacks both territories, they pin the attacks on the Evil territory on the Good Characters so the Evil characters can declare war and both sides would kill each other. Then the Evil Characters destroyed any excuse that they were as much pawns as the Good characters with their brutal torture and murder of Strawberry Shortcake. The Good Characters, led by Butters-turned-Messianic Archetype, still won the war and imprisoned the Evil Characters instead of making a truce. Also, Strawberry Shortcake was resurrected with every other Good casualty.
• In season 20, Lennart Bedrager is willing to start World War III to get back at Gerald for cyberbullying Fraisha Holengulf the volleyball player into committing suicide. Also, because he probably thinks it's funny.
• In "Quest For Ratings", just to show how much ratings are Serious Business for AV teacher Mr. Meryl, Craig's punishment for ending up with a significant drop in ratings is to not only be suspended from school but also have his teacher write a recommendation to have his testicles surgically removed.
• In "Super Fun Time", Pioneer Paul shoots and kills his co-worker all because he broke character to save himself from the terrorists. Even the terrorists are left appalled by this.
  Pioneer Paul: What he meant to say, kids, is that we ain't never heard o' no fancy door code 'cause in our time, we gots to rely on wood locks and sich.
  Franz: Goddammit! You people are fucking insane!