Teens Are Monsters in Western Animation.
- American Dad!: "1,600 Candles" has Stan and Francine dreading Steve going through puberty due to how angry and destructive his older sister Hayley was when she was developing.
- Angela Anaconda: The titular character's twin teenage brothers Mark and Derek.
- Parodied in Animaniacs via the Katie Ka-Boom shorts which took it to outlandish extremes; Katie literally turns into a monster whenever she's upset. However, Katie's issue was implied to be a much more specific teen problem.Katie: I am NOT overreacting! I'M A TEENAGER!
- Arcane: Jinx post Time Skip. Jinx is in her late teens and is also a mass-murdering psychopath/Mad Bomber who would commit acts of violence and cruelty on her own accord.
- Amphibia: Sasha Waybright is a thirteen-year-old Manipulative Bitch who delights in commanding people around and being in charge. She drops this trope after her Character Development.
- Avatar: The Last Airbender:
- Princess Azula is nearly the lone exception to an otherwise subverted rule. She's the one prominent teenager in the entire show who starts out evil and remains evil from beginning to end. However, she ends up being exposed as a very tragic, messed-up person, so not many people in-show or out of it tend to see her as a "monster" anymore.
- The next most prominent example is Jet, who attempts to kick an old man in the head and flood a whole village of innocents in his intense rage towards the Fire Nation. He's the leader of a gang of teenagers willing to commit murder and other dark crimes for no other motivation than revenge and gets called a monster in-universe by Katara. He's changed his approach by the next time we see him, insisting that nobody else will get hurt when he tries to expose two firebenders disguised as Earth Kingdom refugees but is forced to learn that Redemption Equals Death when his plan backfires on him.
- Beavis And Butthead: Both of the main characters act in such a way that it's easy why one can see them as total assholes, while with little respect for authority.
- Kevin 11 of Ben 10 is an interesting inversion, in that he was an Azula-level Ax-Crazy Enfant Terrible sociopath as a preteen kid, but calmed down into a genuinely heroic Jerk with a Heart of Gold by the time he actually became a teenager.
- Codename: Kids Next Door:
- A milder version of this trope, which is coupled with Adults Are Useless. The dubious situation of teenagers is that they are being loyal minions, perhaps based on the logic that teenagers actively try to behave like adults. Although they also betray the adults as well, possibly in reference to the fact that teenagers are also more rebellious against adults than kids are (or just to show that they are indeed bastards).
- Many characters in the show enter an "outgrowing" phase shortly before their 13th birthday and become the rebellious bastard stereotype we know and love when they finally hit the big 13. Though not all of them are affected by this. Some teens (and a few adults) are hired as black ops double agents for the KND.
- And there's Laura, who, whenever she gets angry (which is really easy), transforms into a monstrous teenager.
- The Crumpets:
- Caprice tends to be this out of the teenagers despite that she's not always evil. She can be cruel to her siblings like putting them in dangerous or graphic photo-ops so she can earn social media attention, and also towards her adoptive teenage cousin Cordless. She runs away from her family to live with her rich uncle and aunt (and risks replacing Cordless as their child), develops an autobiography of her new life, and insults her family and best friend Cassandra (after failing to read and respond to Caprice's text messages asking her to join) in one episode. She also dislikes animals and hurts them prominently in at least two episodes.
- Cassandra also counts sometimes, like when she gets rebellious at her mother (bonus points if she growls) or if she tries to prevent her crush from falling to a TV weather reporter, whether she disguises as either of them or kicks the satellite dish on the Crumpet house.
- Ed, Edd n Eddy:
- The Kanker Sisters are Barbaric Bullies indicated to be teenagers. Lee, the oldest sister, is easily the worst of them.
- 15-year-old Kevin is a Jerk Jock who often torments and humiliates the Eds (especially Eddy) for his own amusement. He does have his Pet the Dog moments, though.
- The Fairly OddParents!: Vicky. She's consistently painted as an evil babysitter, but it only brings up her age when Rule of Funny applies. More than likely that she has always been and will always be evil. Her age is a side-effect of being a babysitter. In one episode, she's a member of a whole club of evil teen girl babysitters. But it's not likely they'll be brought up again.
- Mac's 13-year-old older brother Terrence in Foster's Home for Imaginary Friends. In the pilot, he and Duchess plan to kill Bloo, and most of his life is devoted to making Mac's a living hell. Additionally, while children typically make cute, friendly imaginary friends, teenagers more often than not produce destructive kaiju.
- Gravity Falls:
- Parodied in "The Inconveniencing". The abandoned convenience store Dusk 2 Dawn is haunted by the ghosts of Ma and Pa Duskerton, its former owners who didn't like teens hanging around the store in life "with their boomy boxes and disrespectful short pants", so they banned them. However, the teens retaliated... by playing incredibly tame rap music and dancing in the parking lot. Ma and Pa thought the lyrics were so hateful and shocking that they dropped dead from heart attacks on the spot.Rapper: Homework's whack, and so are rules! Tucking in your shirt's for fools!!
Ma and Pa: '''NOOOOOO!!!!''' *dies* - Robbie is portrayed like this for most of the series, and not just because of his rivalry with Dipper over Wendy's affection (which is ridiculous anyway due to Dipper’s age). In "Fight Fighters" he forces Dipper to fight him, even though Dipper is 12 years old, and acts like a brooding jackass almost every time he appears. He finally mellows out somewhat when he begins dating Tambry in "The Love God".Soos: I don't know, Dipper, teens are dangerous! Those hormones turn into like, killing machines! My cousin Reggie got in a fight with a teen once, and the guy broke like, all his arms, all his legs, and I think killed him or something. Me and Reggie were just talking about it.
- Parodied in "The Inconveniencing". The abandoned convenience store Dusk 2 Dawn is haunted by the ghosts of Ma and Pa Duskerton, its former owners who didn't like teens hanging around the store in life "with their boomy boxes and disrespectful short pants", so they banned them. However, the teens retaliated... by playing incredibly tame rap music and dancing in the parking lot. Ma and Pa thought the lyrics were so hateful and shocking that they dropped dead from heart attacks on the spot.
- One episode of King of the Hill has a gang of teenage paintball delinquents making Hank and his buddies' life a living hell (to the point of doing drive-by shootings with the paintball rifles) just because he took a stand for Bobby earlier. The trope's even mentioned when they get Bill to pull a Wounded Gazelle Gambit so Hank and Dale could pick off two of them:Hank: You were right, Bill. Teenagers are cruel. They'll pick on the slowest, heaviest... (realizes he's talking exactly about Bill) Well, the important thing is, you were right, Bill!
- Miraculous Ladybug:
- Chloé Bourgeois is a spoiled Alpha Bitch who uses her status as the mayor's daughter to have her way while harassing those beneath her like Marinette Dupang-Chang. She had a few Pet the Dog moments in earlier seasons, but Flanderization sets in the Season 3 finale and she relapses into this trope. Overall, she's spiteful, mean, couldn't care less about anyone besides herself, repeatedly abuses her peers and family, and willingly teams up with Hawk Moth over petty reasons. She gets much even worse as the fourth season begins, especially after being influenced by Lila Rossi.
- 13-15-year-old New Transfer Student Lila Rossi is a Consummate Liar and Bitch in Sheep's Clothing who outdoes and "mentors" Chloé in being horrible — come "Revelation" and "Confrontation", "Lila" turns out to be a false identity as she weaseled her way into other families under aliases and manipulates Chloé before abandoning her once getting what she wanted from their arrangement.
- Félix Fathom, Adrien's identical cousin, is a Justified case since he was tormented by his dying father over the truth of his existence and forced to do things against his will. This made him into a Jerk with a Heart of Jerk and Well-Intentioned Extremist who played a long game with his uncle Gabriel, whom he later learns is Hawk Moth, and exploits at the cost of further endangering Paris.
- Mother Up: Neighborhood teen Joel (the only teenager seen in the first season) hates everyone, especially his stepfather Greg who he repeatedly tries to maim, listens to harsh music, vandalizes things and plays ultra-violent video games.
- The My Little Pony: Friendship Is Magic episode "Dragon Quest" reveals that this is a species-wide issue when it comes to adolescent dragons. At first, they're simply loud, obnoxious Jerkasses, but then it's revealed that one of the things they like to do for fun is kidnapping and smashing phoenix eggs. When the eggs hatch, their leader decides that they'll take the newborn babies instead.
- The Powerpuff Girls:
- Two episodes featured the Smith family, one member of which was their angry teen son Bud. In the first episode, Bud's entire appearance consisted of him yelling something typically teenagerish at his father, such as "I hate you!" and "No one understands me!" The second episode, which features the entire family as villains, provides every member of the family with a motivation for why they hate the Powerpuff Girls — and Bud's is "I hate everything!"
- There's also the Gangreen Gang, a group of teenage delinquents with inexplicable green skin (the source of their name). They're not particularly successful criminals but tend to be a rather sadistic, destructive lot and indulge in cruel, petty crimes like bullying little kids or tormenting animals.
- The South Park episode "Help! My Teenager Hates Me!" features a group of teenagers who play at an air-soft field. They are all portrayed as vindictive, foul-mouthed, aggressive, and self-centered, ticking off all the boxes for negative stereotypes of teenagers. Gerald even tells his son Kyle that the brain of a teenager is equivalent to the brain of a psychopath.
- The vast majority of villains on Static Shock are superpowered teenagers. As are the heroes.
- Superman: The Animated Series had an episode where Granny Goodness created a crime syndicate out of wayward teens in Metropolis, using Apokoliptian technology, love, and twisted sadism.
- Most of the Sherman High students in Sym-Bionic Titan are pretty cruel to the show's main trio when they start school there. Some of them get better.
- Velma: Velma grew from being an Enfante Terrible to this in her teen years. She constantly shows herself to be a cruel, selfish, vengeful, and mean-spirited person who uses her so-called friends as pawns, is a bigot towards anyone she views as more popular or privileged than her, and has a huge Lack of Empathy for everyone else's problems. Her most noted example of her status is when she is the only one shown happy that Fred's mom, Victoria Jones, was killed by stalactite and was hit by Norville's bullet and impaled. All she cared about was that she "solved" the mystery and not the fact that Fred had to see his mother die so horribly, even if she was trying to remove his brain. Also, she locked her father, his girlfriend, and her half-sister (who is a baby) out of the house so she could live with her mom only.
- The Wacky Adventures of Ronald McDonald: Scared Silly plays the trope for laughs at the end of the live-action Framing Device, where Ronald McDonald's dog Sundae is watching a sequel to the dinosaur movie he was viewing in the beginning and explains to Ronald that the sequel involves the baby dinosaur from the first film becoming a teenager with an appetite for destruction.
