There are some mild dissimulated references throughout the series, because it's between fantasy characters and this makes them less controversial. For example, in the episode "The Storm" Alan the balloon wants to cheer up, and he explains that Gumball needs to blow in his only hole. After, Gumball has a disgusted face while Alan is happy. Darwin does it on screen in "The Traitor".
A few male characters are sometimes seen nude, but their private parts are seen pixelated (also, when Darwin is naked, his legs are pixellated sometimes). In a lot of episodes Richard shows his pectorals (in Season 1 nipples' shadow are seen). Butts are seen as well.
There is some little kissing. Gumball has a crush on Penny the same way that Carmen (a cactus) has a crush with Alan (a balloon).
In "The Knights", Gumball angrily walks in on Richard showering. Richard is then forced to shower outside, later on, Penny and her father witness it.
Gumball has a crush on Penny. In "The End", he believes that the world will end in 24 hours, and tries to "marry" her. She rejects the marriage, kisses Gumball and says that shouldn't stop him from asking in 12 years. After, he complains about the love he has with her, but suddenly offers his ring (a donut) to Carmen, and the scene cuts out.
In "The Pressure" there is some mild innuendo: some girls talk about her boyfriends; Masami calls Darwin "sweet cheeks" and the like; Gumball falls on a swimming pool and ends with his body fully red, and then grabs ice cream and puts them on his chest (something that remembers pointed breasts), and Rocky says to him "Hey, dude! Nice bikini!" and Gumball says "thanks" comfortable; Rocky says that when he opens his heart all his girlfriends go out; Gumball accidently kisses Darwin offscreen while the treehouse falls after being chopped down and Gumball describe it as "being run over by a unicorn".
Sometimes, some characters accidentally go into the opposite gender bathroom (principally Gumball). For example, in "The Mustache", Gumball and Darwin don't realize that they are in it, and are complaining about puberty in it. Then, a girl explains they're in the girls bathroom. She is in one of the stalls. Only a bit of het legs are shown. In "The Fight", Gumball is forced to run through the girls bathroom while running away from Tina.
In "The Prank", Richard is fully naked, but his body is covered by a raft. Gumball asks where his clothes are, Richard says "I ate them."
Gumball calls Penny "hot" in "The Party" and in "The Date".
In "The Fridge", Richard shows a Sausage Pen, a semi-peeled sausage that seems to be a penis. He says: "Everything it writes is delicious." and Nicole says: "Mmmm... innovative! But... ultimately useless.", causing him to be disappointed.
In "The Party", in the aftermath of a party, Terri is lying on the ground with a bra on. This is not explicit as Terri is a teddy bear made out of paper and the bra is pencil-drawn. Also, in the episode "The Night", Teri is seen naked but nudity is pixellated (however, looks like she's in underwear).
In "The Dress" Gumball is forced to dress as a bride and everyone thinks he's a "lady". In the same episode he receives a love letter by Darwin to go on a roller coaster and in the end it says "XXX"; for Gumball this meant "how extreme it will be".
In "Halloween", a fantasy female character wears swimming suits and a male character precipitately looks at the girls' bath.
In "The Shell" there is a part where Gumball accidently sees Banana Joe looking at fruit being peeled off online and he looked like he was looking at porn.
In "The Saint" there's one scene which shows some photos showing Darwin disguised as Alan with the intention of Alan losing his couple. However, its noticeable a cut between two of these photos, because some of the frames show a photo of Leslie smiling.
In "The Nemesis", Gumball says he found the thing that Rob misses for being an enemy, and Darwin sees him holding melons and askes if that's what he misses.
In "The Hug", somehow pressed by Darwin, Gumball is bound to be a friend of Hot Dog Guy and they hugs very often. In one point of the episode, they're sleeping in a tent near Gumball's house, and he wants to move Hot Dog Guy's hand on another side, because he do not let him sleep, so he puts on him. Then Hot Dog Guy wakes up, both make their smile and, with the camera in off seeing their shadows, they do their strange hug.
The episodes "The Extras" and "The Love" feature homosexual characters. Richard is dressed as a woman in "The Safety".
In "The Nest", a man having a shower grabs a turtle instead of the soap and it's put on his lower parts causing him to yell (nothing revealing is seen).
Sometimes, characters yell at each other, and when they hit each other sometimes appear "red" wounds and black eyes, but nothing very worrying.
In "The Prank", Richard is shot by a tranquilizer dard, like Nicole in "The Shell" and Darwin in "The Origins: Part Two".
In "The Dream", Darwin said he wanted to eat Gumball (in the line "Dude! Where were you?! I've been in this car for like five days! I was so hungry, i was considering eating you!"); in the same scene appears with Gumball's arm bitten. However, it isn't worrying because after appears normal.
In some episodes characters apparently die for comic effect (Lego-like characters lose arms and the head -but still alive, Sarah the ice cream melts, Anton the sandwich is chewed, Alan the balloon explodes, Banana Joe is trampled, etc.) until the next scene/episode.
Sometimes characters electrocute, principally by tasers. In "The Skull", Gumball, Darwin and Clayton use shock therapy to cure their lying. In "The Crew", in the final seconds a group of old people are electrocuted off-screen by a taser. Both scenes were censored in the United States for avoid a TV-PG rating.
In the episode "The Lesson" some of Gumball and Darwin's detention mates fight off screen. When they escape the room, some jelly (which resembles blood due to one of them being a cherry) splatters on the door window. In "The Roots", Richard kicks off his ears and a tooth briefly (no blood).
There are various cartoon violence in almost all episodes, such as a car falling from many meters, people in hospitals, destruction of walls and houses and explosions, but in a comical context. In some episodes can be seen some mildly fantasy-looking organs like hearts ("Halloween", "The Debt"), brains ("The Genius", "The Goons") or kidneys ("The Gripes"). In "The Traitor", Gumball and Darwin want to do a trasplant in a balloon and all blood and organs are invisible, so they say "there's air everywhere".
In the episode "The Wicked" there's a lot of more fantasy violence than usual; can be seen animals attacking people and a lot of chaos and destruction, especially with the constant attack to Ms. Robinson (who at first laughs attacking them) at the end of the episode.
In "The Wand", Gumball and Darwin are out all of them and they are shown as red meat and some bones, and in another moment some parts are mutated (like Gumball and Darwin's face are their butt and their butt are their face).
The episode "The Fury" contains a fight scene that can be easily considered one of the most violent of the series, despite it doesn't feature blood, according to CN's standards the episode could be easily rated TV-PG-V, but it received a TV-Y7-FV as usual.
Vomiting and spitting is present in the show but it's very rare.
Frequent uses of mild colloquial language including "darn", "gosh", "goodness", "dude(which is not a swear word)" and "butt".
Some name-calling including Gummypuss (said in "The Meddler" and "The Downer") and Nincompoop (said only in "The Mystery"). A character from the series is named Gaylord.
The word "bimbo" is said once in "The Storm" by Gumball (for U.S. airings, the word is censored with the word "coward" instead, but the word still appears in the closed captions if they're on). Gumball says "what the actual what?" (instead of "what the actual f**k?") in "The Fury".
"What the..." and "what the what" are used often, but during the series Gumball says curious euphemisms (like "droid", "derp", "pucks", "buzz", etc.) for that word that comes with "what the".
However, in the episode "The Safety", Gumball ensures that only knows these swearing autorized by his mother (but in "The Crew" he reads Darwin's thinking and promptes him to moderate his language, like Richard does with Cartax in "The Routine", and in "The Virus" he says a virus is gaving him "rude gestures" although nothing is seen).
"OMG" is said (spelling) or written sometimes. "Shut up", "jerk", "heck" and "nipples" are said in some episodes. "Sucks" and "suckers" can be heard in some episodes as well, but never in a sexual context.
In the episode "The Mirror", the shopping channel is seen on TV, and Gumball says: "Dude, I think I'd prefer a life of damnation in limbo rather than having to watch that."
In the episode "The Roots", when Gumball talks in a fish-friendly language, he says: "Minnow you've been giving us a lot of carp about this whole fish thing".
"Gosh darn" is used 60 times throughout the series. "Dagnabit" is used several times as well.
Nothing really, but in "The Mustache" Gumball and Darwin become "men" after accidentally eat Richard's vitamins, and some characters drink soda or coffee during the series. In "Halloween" some characters drink a magical potion for see ghosts and/or become it. In "The Banana" Mr. Small drinks a herbal tea that very relaxes him. In "The Phone", Gumball sits on a firecracker for silence it and he expulses smoke from his mouth.
Not specially a frightening/intense thing, but in the show some black humor is present and discussed (like government and business corruption, social groups, consumer society, despotic behavior, etc.), specially in seasons 3 and 4, that only mature children and adults may understand.
Carrie is a ghost. In "The Ghost", she continuously robs Gumball's body because she is unable to eat in her ghost form. This can be quite scary for very young viewers.
In "The Microwave", Gumball and Darwin make a monster out from a microwave. Some monsters and things might scare someone.
The faces from certain characters in some moments of the series, especially in Season 1, like Anais' resigned face in "The Kiss", can scare to very young viewers. Some scenes can be mildly intense as well.
Some scenes from "The Night" like Larry's sealed mouth and Daisy's dream can be scary for some viewers.
The episodes "The Joy" and "The Parasite" can be scary for some younger viewers.
Official Australian rating for Season 1 DVD: Rated PG for mild comedic violence and crude humor.
Official British rating for the first 12 episodes: Rated PG for mild comic slapstick violence, sex references and scary scenes.
Suggested age: +10.