One of the most known cases of this trope (in the days before South Park and Seth MacFarlane's shows, but right around the time that The Simpsons was considered popular/controversial) is when Beavis and Butt-Head (a pair of idiotic teenagers who do dangerous things and try to get laid) caught heat for driving younger, more impressionable viewers into imitating their dangerous stunts (mostly setting things on fire, putting dogs in laundry machines, and dropping bowling balls from bridges). When news of a boy burning down his trailer and killing his sister cropped up, the boy's mother protested the show's content (even though the family didn't have cable at the time of the incident). As a result, Beavis could no longer display pyromaniac tendencies or grunt, "Fire! Fire!" (though the movie and the revived series brought those back), most of the older episodes had to be edited to remove anything considered imitable.
The Seth MacFarlane cartoon franchise, which boasts such shows as The Cleveland Show, American Dad! and the always-polarizing Family Guy, is one of the most frequent targets of the claim in recent years. Critics, including the Parents Television Council – in harshly criticizing the frequent very adult plots, extreme violence, crude language and lewd sexual situations – cite the fact that the show is animated, have child-friendly businesses (such as Burger King) as frequent advertisers, have merchandise marketed to children and its airing during early evening hours when children are potentially in the audience. Those defending the show often point out that the show's intended audience is not children and that some won't allow their children to see it, but those claims have often been denied by the PTC and others. Even more so if one buys the DVD release. Some adult cartoons, like The Simpsons, are written to comply with broadcast standards, so what you see on television is (with few exceptions. The DVD versions of "Marge Gets a Job," "New Kids on the Blecch," "Viva Ned Flanders," and "Sunday, Cruddy Sunday" edited out Mrs. Krabappel's line about Bart feigning Tourette Syndrome, Mr. Burns calling Smithers a "Chinaman," Homer figuring out that Barney's birthday is on the same day as Hitler's, and a sexy Superbowl commercial about The Catholic Church respectively. While most of these were for offensive content, the Hitler line was censored due to a tragedy that occuredon that date) what you'll get on the DVD. The MacFarlane cartoons are written first and then censored for broadcast, so the DVD versions are often more explicit.
One of the biggest is South Park; despite airing at a time when kids should be in bed, some kids watch it anyway. Despite the animation using a paper cut-out doll style, and the main characters are children, it is full of swearing, violent death, gore (especially in the later seasons), uncensored cartoon nudity, implied and explicit sexual abuse (including scenes of rape), and child abuse both implied and confirmed. People with various prejudices aren't always directly punished, and childish innocence is rarely a good thing, which might confuse children. It also makes fun of Political Correctness Gone Mad and features a manipulative, sociopathic, anti-Semitic little boy (Cartman) as one of the show's most popular characters. It also doesn't help that from seasons one to six, the theme song was more cheerful and unassuming, which lured a lot of people into thinking it wasn't that bad (despite the TV-MA rating and that warning that says all the celebrities are impersonated and the show's content is so vulgar that nobody should watch it)
Now that the show had 20+ years of notoriety preceding itself, this doesn't happen much anymore. That said, when it had a short-lived syndicated run on free-to-air TV, the FCC received complaints of kids overhearing the show or trying to stay up late to see it, and it was put on halt until the 18th season in Fall 2014 (which is why King of the Hill and Futurama now rerun in syndication and why Comedy Central airs the the syndicated episodes on their channel).
The Simpsons (the animated series said to be the grand-daddy of all modern adult TV animation) has dealt with adult subjects like animal abuse, child abuse, politics, alcoholism, sex, religion, class inequality, and juvenile delinquency, but back when it first aired, a lot of people didn't accept it as an adult cartoon because of how simplistic the animation and art was, and trashed it for corrupting youth due to the subject matter and having Bart Simpson (who, back then, was written as a more destructive, 1990s spin on Dennis the Menace) as the main focus of the stories. It also didn't help that Simpsons merchandise back then were sold as children's toys.
The Simpsons was even, in 1991, declared by Channel 4 to be the Greatest Kids' TV Show ever, despite not actually being a kids' show.
Word of God says it was never meant to be a kids' show and the bright color scheme was meant as an attention-grabber for FOX executives and viewers who just happened to be channel surfing.
Before this, the characters made a cameo appearance in the celebrity version of the Sesame Street segment "Monster In The Mirror".
This was done in-universe in the very first Treehouse of Horror, even though the subjects mentioned weren't actually for children:
Homer: Oh, no, Marge! Come on, please!
Marge: Homer, I’m not sleeping with the lights on. Theyre just children’s stories. They can’t hurt you.
In 1998, King of the Hill was nominated for a Kids' Choice Award, despite being an adult show that deals with similar subjects touched on both The Simpsons and Beavis And Butthead: Political Correctness Gone Mad, worker incompetence, gay and transsexual issuesnote as seen in the episodes "My Own Private Rodeo" and "The Peggy Horror Picture Show", spousal abuse, suicide, mental illness, infidelity, marital strife, death, sexual harassmentnote and not just man on woman; the episode "That's What She Said" depicted male on male harassment with a character making lewd jokes that does offend some of the men who work at Strickland Propane, and "Jon Vitti Presents: Return to La Grunta" had Hank humped by a dolphin, with the hotel staff not taking him seriously, drug abusenote mostly tobacco and marijuana smoking and alcohol consumption, and indecency in the media. As mentioned on the Animation Age Ghetto page, many children and teens stayed away from this show because they found it boring (which is what a lot of detractors of the show have said about King of the Hill in comparison to Beavis And Butthead, the latter of which is more chaotic and raunchy).
Teletoon, the Canadian version of Cartoon Network, specifically airs warnings before and during each show from 9pm on (the "Teletoon at Night" block) that the shows are not intended for children. They actually build in a margin for error in that they start with an hour of Futurama and then come the shows like Moral Orel, Archer, and Squidbillies. By the time the later shows roll around, the warnings include comments like "...meant for 14 years of age and older. And if you aren't 14, what are you doing up this late?"
Slacker Cats. Despite its sexual humor (like the first episode alone showing necrophilia), it aired on ABC Family. And no, it wasn't because the original sale from the Christian Broadcasting Network to Fox/Saban contained a stipulation that the channel contain the word "Family" in the name forever no matter who owns the network (this was kiboshed when the network was renamed to Freeform in 2015). It still remains a mystery how it lasted to 7 episodes.
Looney Tunes (the original shorts from 1930 to 1969) have, according to its directors and how it was distributed back then, been meant for general audiences (i.e., kids and adults, though most of the humor in the Looney Tunes cartoons would either be too risqué for kids or wouldn't be readily understood by kidsnote the latter of which would be things like jokes about popular celebrities or events at the time. The original Looney Tunes cartoons were pretty much what The Simpsons, South Park, and Family Guy would be like if they were made in the days when animated shorts, live-action shorts, and B-movies were part of the movie-going experience). When the cartoons were syndicated for TV, a lot of the cartoons had to be edited or banned outright so it can appeal to kids (and a new generation of adults who would see some of the outdated jokes and scenes as racist, sexist, or un-PC). The DVD releases of the cartoons have the shorts uncut and even include a warning in the beginning, stating that the cartoons are products of a different era and should be seen from a historical perspective.
And while we're talking about works created before the Animation Age Ghetto kicked in, some children's TV cartoon anthology slots have included Betty Boop cartoons, some of which were risque enough to be attacked by Moral Guardians at the time.
If you turn to the search menu for your DVR and search for Archer, you will find it labeled as children's programming, despite the excessive bloody violence, copious female nudity, and sexist/racist/overall politically incorrect humor.
Fish Police was a Hanna-Barbera cartoon about anthropomorphic fish, with colorful backgrounds, many fish-themed puns and a Disneyesque animation style, very loosely based on the comic book series and aired as an early competitor to The Simpsons (back during its Golden Age when it was seen as the greatest American television show, and not a lesson on why most TV shows should just quit if they start to run out of steam). It was also filled with content that went beyond what can acceptably be considered Parental Bonus in a "kids'" cartoon — including an episode that had an underwater version of a red light district (a part of an urban neighborhood filled with legal and illegal sex businesses, such as sex toy stores, X-rated video stores, strip clubs, underground sex clubs, illicit massage parlors, and, of course, pimps and whores on the street). What's worse is that in some countries, it aired on Cartoon Network back-to-back with children's shows.
Duckman: It's about a cartoon duck, and it's made by the nice people who brought us Rugrats. If only it weren't for the offensive language, politically-incorrect subject matter, rampant female fanservice, and sex-related jokes.
Stressed Eric also qualifies (although Klasky-Csupo didn't animate season 2). There's an entire episode about sex. But that didn't stop many young kids from watching the show...and subsequently getting terrified by the end of every episode, where Eric's stress vein strangles and kills him.
The animated shorts collection Batman: Gotham Knight features horrific violence - and unlike the live-action version, it isn't bloodless. The usually more conscientious commonsensemedia.org thinks Gotham Knight is appropriate for 11-year-old children (in comparison, they unanimously thought otherwise for The Dark Knight). Because it's animated, and it's about Batman, right? Thankfully, none of the shorts featured The Joker, there would be kids in therapy. Some stores even sell the film in the children's section, and it was even aired on Cartoon Network, albeit with a TV-14 rating and some of the violence toned down.
Batman: Year One and Batman: The Dark Knight Returns are rated PG-13. They earned those ratings, with their frank depictions of prostitution, violence (particularly against women), hard-edged vigilantism, and Anti-Hero-ism, with The Dark Knight Returns having both a male-to-female transsexual Nazi with swastika pasties covering her breasts, as well as the gruesome massacre and death of The Joker. Not only does DC Showcase: Catwoman have graphic portrayals of strippers, but Catwoman takes part herself.
All three movies mentioned above are part of the line of DC Universe Animated Original Movies, all of which are aimed more towards adults and teenagers than younger kids (the fact that they're rated PG-13 should point this out, though some movies aren't as dark as others) and could count for this trope. The biggest case would be Justice League: The Flashpoint Paradox, which contains very disturbing and Squick-inducing content that manages to surpass The Dark Knight Returns.
Bromwell High. Despite being barely well-known, it is probably the most triumphant example of this trope. It airs on the Canadian kids network Teletoon, so that means it automatically is for kids, right? Wrong. You can never go through an episode WITHOUT major uses of the F and S words, and it features a lot of sexual references (and in Latin America, it also aired on [adult swim] for a reason) yet it got a DVD release by the FAMILY division kaBOOM! Entertainment and airs on the Australian children's network ABC Me. Naturally, the DVD release got a CHVRS rating of 18A (the equivalent of a US R rating).
Brickleberry. At first glance, someone may think it's perfectly fine for kids since the animation and art looks like something from a Saturday morning show in the 1990s (or the early-to-mid-2000s since it was Adobe Flash-animated in season one and traditionally animated with digital ink and paint for proof of concept in seasons 2 and 3note the 1990s was the last decade to have traditional animation with cels and regular ink and paint), has talking animals, and includes a lot of voice actors from more kid- and family-friendly shows, like Tom Kenny and Tara Strong. It's...not. If the cold opening of the first episode (where Steve shows a bunch of horrified Boy Scouts a meadow filled with animals having sex) doesn't make you believe, then look up all the reviews (most of which are negative) about how this show is an excessively vulgar clone of Family Guy and South Park, with none of the self-aware goofiness or scathing satire of either show.
Spawn: According to Todd McFarlane, when he first started pitching an animated version of Spawn, the networks he talked to wanted to make a Saturday morning version. Right down to talking animal sidekick, though at that point he may have been being sarcastic in his recollections. It seemed none of the big-wigs realized that a character whose name was short for "Hellspawn" and who was horribly burnt head to toe and fought against multiple angels and devils across Earth, heaven and hell itself wasn't a good fit alongside the light-hearted fair common to those slots. Then again, when he finally got the nod from HBO, airing past-prime-time with numerous warnings of its content, people still complained that this 'kiddie cartoon' was so graphically violent and sexual, leaving him feeling like he never should have bothered in the first place.
Drawn Together: What seems like a cartoon with parodies all our favorite types of cartoon characters (including anime-style and video game characters) together is actually a show with tons of Black Comedy, otherwise highly offensive and politically incorrect humor, Squick, and Body Horror. But kids still watched it anyway when it came out. Conversely, The Amazing World of Gumball is also about different types of cartoon characters (and some that aren't, like live-action chin puppets, Muppets, Atari-style video game characters, and paper cutouts, to name a few) living together and interacting with each other, but is significantly more family-friendly in comparison (even though the latter show has been known to push the limits of being "family-friendly").
The streaming site Flixanity has Clone High (a series about clones of famous historical figures as stock high school teen show characters, like the Jerk Jock, the Alpha Bitch, the apathetic Goth girl who hates the popular kids, has a crush on The Everyman protagonist, and dresses in black, the party animal and comic foil to the protagonist, etc) listed as a kids show. While animated historical series for kids exist (Liberty's Kids, Histeria!, Horrible Histories, Time Squad, and Sherman and Mr. Peabody's Improbable Histories), this one is not all that educational and not all that kid-friendly.
Rick and Morty seems like an innocent children's show at first, being about a young boy and his adventures with his Mad Scientist grandpa. However, it isn't. It contains plenty of violence, gore, threat, and peril that's better off in teen and adult entertainment. It also has several sex jokes, a good deal of cursing note The syndicated and streaming versions are TV-14 and bleep the f-bombs, but the Blu-Rays don't, and thus carry a TV-MA rating. and adult themes, up to including a disturbing Attempted Rape at the main character, and the aforementioned scientist is an uncaring sociopath and raging alcoholic who always puts his family and grandson in danger due to his bizarre experiments. Despite the "super-scientist on an adventure through the universe" plot, it's definitely not Doctor Who. It doesn't help that there is an innocent spinoff mons parody game called Pocket Mortys, that is only rated E10+. Both season sets also appear in the children's section of Overstock.com, even though other Adult Swim shows have managed to avoid this. It doesn't help that it occasionally starts the [adult swim] block after Cartoon Network ends.
The Dutch cartoon Purno de Purno is actually advertised as a kids show, despite it having enough mature content that it would undoubtedly get an 18+ rating outside of the Netherlands.
Kaeloo: The show features talking animals playing games while living in a place called Smileyland. That being said, there's sex jokes, drugs, alcohol, suicide attempts, and even a few Attempted Rapes.
While the first four seasons of Samurai Jackare intended for kids, the fifth revival season on [adult swim] certainly is not. While it retains the same visual style and humour, it also gained a TV-14 rating, which allowed it to be far Darker and Edgier than previous seasons. The title character contemplates and later attempts suicide, there's a lot of onscreen blood and graphic onscreen death (for example, in the second episode, a character gets their throat slit), some mild language (such as a certain "penis"), and adult themes such as Jack having to convince himself that it's justifiable to kill people in self-defence.
Due to international lack of an Adult Swim block, Home Movies ended up airing during children's timeslots on Cartoon Network UK, as well as on Canadian youth station YTV with a PG rating. Despite its child cast, the show is very distinctively aimed at adults; both due to the occasional innuendo/salty language as well as the pop culture references only adults would get. It is worth noting that later seasons (with more envelope-pushing episodes such as "Curses") didn't finish its run on Cartoon Network UK, and later moved to Teletoon in Canada, where it aired with an 18+ rating, which, to be fair, is a little too out of line.
Greg the Bunny actually aired on Australian TV in the morning alongside actual children's programs. Not for long though.
The Maxx has an animated adaptation. Needless to say, showing this to your kids is not a good idea, but it aired on Teletoon for a while anyway.