There are tons of cartoon innuendos that happened in older shows, from Spongebob to Invader Zim, and honestly, it's a very surprising fact that some of these jokes even made it into the shows at all. There are some shows like Ren And Stimpy or Mr. Meaty that made their living off of Gross-Out humor and body horror, which doesn't seem like a sustainable model for a kids' show in the first place.
Invader Zim was particularly bad about this since Nickelodeon specifically did a call for a television show that would cover their 12-16 year old demographic. Let's take a look at some scenes like this that didn't quite make it to air.
Sven Hoek
Ren And Stimpy was always known for pushing the envelope, so much so that eventually John Kricfalusi got fired from his own show. John K. was fired for plenty of other reasons, but the scene that got him canceled wasn't the first time he had gotten a scene pulled from the show.
The first scene that Nickelodeon got rid of was in an episode where Ren's cousin Sven comes over, and Stimpy and Sven spend the day together. The issue is when they hide in a closet together, and Stimpy decides they can play a game called "Sword Swallower". No need to extrapolate that point, but that's why the scene was pulled (although it's available on DVDs for any curious fans).
The Seizure Pokemon Episode
Denno Senshi Porygon is probably one of the most infamous cartoon episodes ever to air. It's the 38th episode of the 3rd season, in which something is wrong with the Pokeballs, so the team enters them to figure out what's going on.
The worst offender in the show is when Pikachu delivers a thunderbolt to a cyber missile, after which the screen rapidly flashes between red and blue. This event gave seizures to tons of people across Japan, putting about 685 people in the hospital. It was known in the Japanese press as the Pokemon Shock. Stocks fell by about 5%, the episode was pulled from the rotation for all time, and it's never been aired again.
Man's Best Friend
This is the actual episode that got John K. fired, in addition to the fact that he was notoriously hard to work with and did so many edits of the show that were already completed that episodes were frequently turned in well past their airing deadline. In the episode Man's Best Friend, we see Ren savagely beat a man with an oar.
The man who was beaten is named George Liquor for some reason, which is already pretty weird for a kid's show. There's a sequence where Ren very visibly snaps in a very realistic and dark way, with surreal, splotchy backgrounds behind him. After this, he beats the man until he's black and blue, swollen, with bulging eyes.
Red Scare Powerpuff Girls
For whatever reason, the Powerpuff Girls show decided it needed to take the George Orwell Animal Farm route with one of their episodes, in which for some reason, a gnome shows up who starts a cult in which they have sacrificed happiness for peace.
The show has an incredibly biased depiction of what Communism is, and regardless of anyone's view on the economic system, it gets into some pretty weird and heavy topics for a kids' show about 3 little girl superheroes. He's also one of the only characters in the series who has straight up been killed, aside from some sentient broccoli and the Rowdy Rough Boys.
Rocko's Flirtation With Adultery
Rocko's Modern Life is pretty well-known for having some pretty racy jokes thrown into the mix more or less all the time. There was one episode where Rocko was a phone operator for an adult phone line, an episode where the word "hell" is plainly shown in text.
In the very second episode of the show, the first segment is entitled "Leap Frogs". The whole plot of the episode is already pretty weird, which can be summed up by saying that his neighbor Beverly Bighead is feeling unfilled in her relationship. She then invites Rocko over to "help her out around the house". She appears naked in the episode, shares an adulterous kiss with Rocko, and they watch a tape of frog mating together.
Bikini James
As with every anime that exists, Pokemon has a beach episode. Weirdly enough though, this might just be one of the more risque beach episodes that's happened in an anime that's aired for children. There's a pretty frequent thing in the show where Jessie and James seem to enjoy dressing in drag pretty frequently, generally for the sakes of a disguise.
The issue isn't with the crossdressing, thee issue enters into the equation when James for some reason decides to don a bikini complete with an inflatable chest. Misty, who is a minor, also partakes in a bikini contest, and the fact that James' chest isn't as flat as hers is played for laughs since it's demoralizing.
Spider-Man
In the 1984 Spider-Man television series, for whatever reason, they decided that they wanted to bring in Morbius as a villain. The censorship that happens with this character is pretty dumb, but at the same time, it's pretty odd that they decided to include this character in the series anyway. Morbius, for anyone who doesn't know, is a vampire. A vampire who drinks blood.
For some reason, there's some weird restriction (or was) against saying the word "blood" or showing a character sucking blood in a children's cartoon. Their solution to this was to make Morbius drink plasma, and he uses suction cups in his hands to acquire it.
A Whole Lot Of Daria
Daria was a series that kind of pushed the limits for its time, both on MTV and on a relic of the early 2000s, called The N. The show frequently explored themes of drugs and sexuality, and despite the fact that it was a cartoon specifically meant for adults and for teenagers, the fact that the show was a cartoon made both censors and parents uncomfortable with the concept of the show exploring such mature themes.
Another issue is that a lot of the sexuality hinted at was not of the heterosexual variety, making homophobic parents in the 90s extremely upset. It's ludicrous that this type of thing would be censored, but it definitely put a damper on the show.
Heff In A Handbasket
Heff In A Handbasket is an episode of Rocko's Modern Life. The show was already well known for going too far pretty frequently, already having the episode Leap Frogs on this list. Apparently, they didn't learn their lesson, because the episode Heff In A Handbasket happened.
There was already an episode where the show explored Hell pretty heavily, but this episode took the Satanic hell imagery to another level. For whatever reason, censors have a major problem with anything that could present Christianity in a questionable light, which is a reason that a lot of Japanese RPGs have been censored when being ported over.
The Kiss
Happening in season 1 of The Amazing World Of Gumball, Darwin and Gumball share a kiss with each other and then go on to talk about how great it was. Having characters kiss in really any kid's show is pretty weird in the first place, but for a lot of censors in other countries, the fact that it was shared by two boys is again what put it over the top.
For some reason, there's still tons of censorship when it comes to LGBTQ+ themes, which in our current year is pretty sad. Oh, the kiss was also an accident and it's played for laughs anyway, so it really makes no sense that it was cut.