One of the Kids

Typically, a main or recurring character who regularly interacts with characters noticeably younger, usually resulting in their maturity level regressing to roughly the same level (if not even lower). They're still capable of acting their age... they just usually don't.

This character shows up most often in anything aimed at younger audiences, where they are Played Straight so as to be more appealing to kids. When Played for Laughs, it's to show an immature or silly character.

See also Wise Beyond Their Years. The difference between this situation and Wise Beyond Their Years is that One of the Kids is rarely treated as any kind of authority; because of their casualness they often do not even earn special respect.

When examples of this trope show up in shows where they are above the Competence Zone of the rest of the cast, they tend to be teachers, which often yields Sensei-chan.

Related to Man Child. Not to be confused with a child who acts like an adult.

Anime and Manga
"Nove: Geez... it makes me feel depressed when I realize that you're supposed to be older than myself."
 * Yukari Tanizaki from Azumanga Daioh could be considered to embody this trope, although she is still treated by her students with respect due to being a teacher (by everyone except Tomo). A respect she abuses without shame.
 * Adults in Lucky Star are often this, to the annoyance of Konata:
 * Her homeroom teacher Nanako Kuroi is envious about students needing to wear uniforms, as she found choosing clothes a chore. And one time, she decided the game when her favorite baseball team lost did not exist at all.
 * Her cousin Yui Narumi is a traffic cop who Drives Like Crazy.
 * Miyuki's mom, Yukari is often mistaken for her big sister, but for her maturity and bearing, she could just as easily be Miyuki's younger sister—part of it has to do with her wisdom at encouraging her daughter to be driven at educating herself. They're practically the same, it's just Miyuki knows more.
 * And let's not get started on her dad...
 * Mira in Godannar.
 * Midori Sugiura from My-HiME is a twenty-something teacher and waitress with a love for history and the occult, but repeatedly tells everyone she knows that she's really only 17 (and also, evidently, Sailor Moon.) Nobody believes her in either case... especially Nurse Yoko, one of her former college mates.
 * However, it's highly likely that
 * In Mai-Otome, the sequel to Mai-Hime, that version of Midori also insists that she's 17. However it's for a much darker reason:
 * Ranma ½ gives us Hinako Ninomiya, the English teacher who is in her late twenties, looks around twelve, and behaves like a six/seven-year-old would.
 * Only in her child form. In her adult form she's usually all business, unless she stays in it for too long.
 * When there isn't something to punch, Dragonball Zs Goku embodies this trope, often acting less mature than his granddaughter'.
 * The Ginyu Force would qualify, playing jan-ken-pon to see who gets to fight who, and betting chocolate bars on the outcome of fights.
 * Dragon Ball Abridged portrays Nappa as this. In this story, he is a borderline retarded Psychopathic Manchild whose dialogue mainly consists of non-sequiturs and random annoyances to his partner Vegeta to the point that "Goddammit, Nappa!" has become his Catch Phrase.
 * "Hey, Vegeta, can we go visit that bug planet?"
 * According to a video announcing Team Four Star's appearance at Conneticon, Nappa's parents died in a tragic spaceship accident when he was a kid, and thus he's never been able to truely grow up. Then again, this happened in an announcement video, so its canon status is questionable.
 * Android 17, in all his fascination with his own personal entertainment, is the kind of Psychopathic Manchild that borders on this trope.
 * Yotsuba&! has Yanda, who during his first meeting with Yotsuba proves that he's just as immature as she is, and big guy Jumbo, who starts a one-sided competition with ten-year-old Miura over visiting Hawaii. Yotsuba's father sometimes acts like a teenage boy with Jumbo, but that may just be because they're childhood friends with a lot of history together.
 * Perhaps best exemplified in chapter 53 when Koiwai leaves Yotsuba alone with Jumbo to house sit while he's away. Yanda ends up stopping by to mooch some hot water and by the time Koiwai comes back the three of them are having a water balloon fight inside the house.
 * Kasugano-sensei from Sketchbook acts very childish at times, which also gets commented on by the students in her art club.
 * Yoshinoya-sensei in Hidamari Sketch is a very good example. She considers herself a young woman before even thinking of herself as a teacher, delights in dressing up in costumes, and is prone to odd looks from her students.
 * Her principal is always extremely disgusted with her, and Hilarity Ensues whenever they meet.
 * Kaneru from Doujin Work is an Office Lady with a very childlike disposition, which makes her bond with Token Mini-Moe Sora very well.
 * Yukiji Katsura from Hayate the Combat Butler.
 * Mrs. Miyaji, and most of the other adults in FLCL.
 * Jack Rakan in Mahou Sensei Negima doesn't count himself among the main cast, but he's managed to become a major player in the kid/teen-filled Ala Alba. Keep in mind, he's old enough to be considered a Badass Grandpa. The other Ala Rubra members (Eishun, Albireo) by contrast had a sense of aloofness to the main cast.
 * America from Axis Powers Hetalia, though he doesn't always act like this. Italy can also be seen as an example.
 * While Daikichi Kawachi has this as an Informed Flaw in Bunny Drop, he quickly grows out of it raising Rin. Rin's mother Masako on the other hand, is a much clearer example, with Rin's biological father (and Dankichi's grandpa) stating in a will that Masako wasn't yet mature enough to be a mother, and Daikichi's impression being that Masako simply doesn't realize the problems she's leaving to other people by not taking Rin.
 * Spirit from Soul Eater frequently acts more childish and inappropriately then the teenage cast. Marie also counts, though is respected by her pupils.
 * Shinigami also tends to act like this, although it's implied much of it is Obfuscating Stupidity as to not scare his students.
 * Michiko Malandro from Michiko to Hatchin sometimes shows signs of being less mature than her daughter.
 * Professor Tsukuyomi Komoe from To Aru Majutsu no Index is this trope personified, as she not only acts the trope, she looks the part too.
 * Ryuuji's mother Yasuko from Toradora! refers to herself as "Yacchan", and makes childish requests like wanting her name written in ketchup on her omelettes.
 * To be honest, part of that is probably how she copes with her lifestyle as a Bottle Fairy hostess . When she really gets mad, WATCH OUT!!
 * Keroro from Keroro Gunsou has some attributes of this, including throwing the occasional temper tantrum.
 * Julia from Rave Master has some aspects of this.
 * Masane Amaha from Witchblade. Good thing her daughter is Wise Beyond Their Years.
 * As time goes on, she gets better.
 * Sein of Magical Girl Lyrical Nanoha. She could act her age if she needs to, it's just that she usually doesn't. She even does an all-out temper tantrum when she gets caught red-handed doing one of her pranks in ViVid.


 * Yomiko Readman lapses into this quite a bit, when she's not killing people. In the manga, she once expresses her displeasure by making a paper airplane with her making a rude face and throwing it at her opponent.
 * And let us not forget who has the mind of a five year old due to brain damage and amnesia.
 * Eriko is unable to cook and irresponsible, leaving her younger cousin Ryuuji to be the grown-up one.
 * Kotetsu T. Kaburagi aka Wild Tiger of Tiger and Bunny might as well be the embodiment of this trope. He is a thirty-something father and veteran superhero. This does not stop him arguing with small children over trading cards, acting like a ten-year-old fanboy at the mention of his favorite superhero (Mr. Legend), riding animatronic rides meant for little children at the mall while waiting for his partner/talking on the phone with his daughter, or replacing the background of his coworkers' cellphones with pictures of himself making silly faces.
 * Irabu-sensei from Kuuchuu Buranko is this. His Adult and especially Stuffed Animal personas act childish, silly and borderline crazy awesome (for normal and average people around him), but when he switches over to his Child persona, he acts serious and like a decent psychiatrist.
 * Maximillian Pegasus from Yu-Gi-Oh! uses a toon deck, and all his duel talk is about his favourite children's cartoon based around a rabbit. He also loves cartoons. A lot.
 * Deconstructed with the unfortunate case of Casca from Berserk. After, the post traumatic stress was so horrible that she went insane and not only suffered amnesia and went mute, but her mind regressed to that of a two-year-old child. She is now in constant need of care and supervision as to prevent anything else bad from happening to the poor woman.
 * Kei's mom in Houou Gakuen Misoragumi. She's also considerably ignorant to go along with her immaturity.

Comic Books

 * The modern take of the Shazam Captain Marvel with the superhero keeping the personality of the boy, Billy Batson, in his Marvel form and the same going for the modern take on his sister, Mary.
 * Captain Marvel is an interesting example of this trope, both because he's a literal example and because Billy is very mature for a kid his age, which is why most people don't catch on to his being an adult child. This also means, that depending on the situation, someone could meet both the Captain and Billy, and come away with the impression that Billy is more mature.
 * Lou's mom in the French comic book Lou! In addition to being a video game addict, she generally tends to behave in a more immature way than her 12-year old daughter.
 * Batman is occasionally portrayed as still being a child at heart. Of course he's equally as likely to written as though Bruce Wayne died with his parents.

Fan Fiction

 * Misato from Nobody Dies has tendencies like this, not unlike her canon self. However, it's presented in a more positive spin to pretty much being a reconstruction of the trope. Her ability to be kiddy and have fun allows her to bond better with the pilots, but she still knows to buckle down and be an adult when it's time to kick Angel butt.

Film

 * Ernest Worrel in the Ernest films, especially in Ernest Scared Stupid in which none of the parents believe him about the disappearances of their children or the troll.
 * Taken in a somewhat more serious tone with protagonist Buck from Chuck and Buck, who appears to have an endless supply of blow pops, a room filled with children's games and toys, and exhibits other odd habits throughout the movie. Granted,.
 * Buddy the Elf in the movie Elf, in which most of his actions are naive, adult child-related, not elf-like. In fact, he's just about an opposite to all of the other elves in the film.
 * Maria from The Sound of Music loves singing and dancing and being a free spirit. This concerned the nuns at the Abbey, as she at first wanted to be a nun.
 * Scarlett from Gone with the Wind may or may not fit this. She doesn't have definite child-like foibles or anything like that, but she's often shown to be extremely childish and immature.
 * Alan from The Hangover definitely acts like a child. Just not as innocent as one, trying to buy ecstasy and saying he wouldn't care if they killed someone while in Vegas.
 * Although Alan does act pretty innocent the rest of the time. He explains buying the "ecstasy" as wishing for everybody to have a good time and is visibly traumatized at the thought of Doug possibly being dead. He also gets into fights with children, is banned from schools because he tried to play with children (which the parents and teachers thought was suspicious), curses in Gosh Darn It to Heck and on the way to pick up Doug, begins singing a Disneyland-like song about how they're the best friends ever.
 * The sequel raises those traits further, and even has Alan having a flashback of the lost evening... portraying every character as a child!
 * It doesn't help that Zach Galifinakis, the actor who plays Alan, has a full-grown beard.
 * The main characters of Mystery Team.
 * Despicable Me: Gru and Vector are not true adults, Gru has Freudian Excuses and Vector still toys with his superweapons. Gru will become a true adult by the end of the movie.

Literature

 * Johnny Chorus from the Ray Bradbury short story "Bang! You're Dead" is a benevolent man-child soldier who thinks the war is a game of Cowboys and Indians.
 * Remedios The Beauty from One Hundred Years of Solitude, combining with So Beautiful It's a Curse to maximum effect.
 * This is in stark contrast with her namesake and technical ancestor Remedios Moscote, Colonel Aureliano's late wife, who was Wise Beyond Their Years.
 * For added irony, Colonel Aureliano is the only Buendia who does not view Remedios the Beauty as this, and instead he insists that she's as lucid as someone who's just come back from a decades-long war.
 * Done very creepily with Pearl in The Changeling.
 * The X Wing Series's Wes Janson is often said to be like this; he enjoys life wholeheartedly and likes pranks, puns, and having fun without caring about dignity. A fellow pilot once says that getting him up to the mental age of twelve, maybe thirteen would be impossible. For all that, though, he does know how and when to put on a straight face and get serious. In combat, he's actually something of a Cold Sniper.
 * In Diary of a Wimpy Kid, almost all of Rowley's friends are little kids.
 * In Death: Bart Minnock from Fantasy In Death was apparently this. It might explain why his murder particularly stuck in Eve and Roarke's craws.
 * Mollwitz in Daniel Kehlmann's Fame.

Live Action TV
"The Doctor: What's the point of being grown up if you can't be childish sometimes?"
 * Gordy the janitor on Ned's Declassified School Survival Guide who helps with many of the main characters' simple plans.
 * Nick Harper in My Family.
 * Spencer from iCarly. Worse, he's a Promoted To Parent older brother to the main character. Yeah...the only parental figure Carly has is more of a kid than she is. At least she's a high schooler—or is it supposed to be middle school? If it's supposed to be middle school, it's Dawson Casting; if high school, then not.
 * Middle school in season 1, high school in subsequent seasons (even though it's all in the same school building).
 * Lorelai Gilmore of Gilmore Girls sometimes was this, especially in earlier seasons. Kirk was a more severe example.
 * In Power Rangers RPM, twin Sixth Rangers Gem and Gemma and to a lesser extent, Dr K, exhibit traces of this trope, due to their childhoods being spent in a think tank producing weapons for the military, never being allowed to interact with other people. This all creates a surprisingly subtle creepy undertone as you realize that, as wacky as these characters are, they have suffered a certain amount of psychological damage...
 * Despite being an over-1100 years old Time Lord, the Doctor in Doctor Who demonstrates a few of these traits.
 * As befitting the Doctor's foil, the Master (especially when played by John Simm) is something of a Psychopathic Manchild.
 * The Doctor is the man who responded to Amy Pond saying "I grew up" with "Don't worry, I'll soon fix that" and who uttered the following quote back in his Fourth Doctor days:


 * FDR from the backwards episode of Seinfeld. He wants Kramer to drop dead, and he wishes on anything he can (wishbone, fallen eyelash, shooting star, birthday cake) that Kramer would drop dead.
 * Tony and Abby from NCIS.
 * Psych has main character Shawn Spencer.
 * Mr. Bean has been described by Rowan Atkinson as being a fully-grown man with the mentality and maturity of a 9 year old boy.
 * Michael Scott from The Office. Explicitly referred to in one of Pam's talking heads in during the "Michael Scott Paper Company" arc.
 * Rules of Engagement: Adam has devolved to this, especially in non-work related scenes, thanks to Flanderization.
 * Richard Castle is this, along with his own mother, who is arguably worse than him.
 * Sheldon from The Big Bang Theory. He may be a genius, but he's by far the most immature. The man has been known to lock himself in his room when upset, run away when worried, and whine when he doesn't get his way.
 * Fits in as a sort-of deconstruction of Child Prodigy: Sheldon is incredibly smart, yeah, but since he couldn't live his child/teen years normally, his emotional growth got horribly stunted.
 * Both Adam Savage and Jamie Hyneman of MythBusters fame occasionally come across as Adult Children, particularly when drunk.
 * Pee Wee Herman, obviously.
 * Sarah Silverman in The Sarah Silverman Program.
 * In the Community episode "Theories and Interior Design" Troy and Abed create a "blanket fort for men".
 * "Artie! The Strongest Man...In The World!"
 * Kathy Geiss, the 40-something-year-old daughter of Don Geiss from 30 Rock, is a literal example of this trope: she surrounds herself with stuffed unicorns and posters of teenage idols, and her tastes in music are limited to John Mayer. Despite this, General Electric's head honchos saw it fit to make her the CEO of the company when her father went into a Convenient Coma.
 * Cliff Huxtable of The Cosby Show may be a doctor, but he often has childlike traits. Mostly he uses them only around children.
 * In The Kids in The Hall, Bruce tended to play these kind of characters. His monologues tended to be grown men with overly naive and idealistic views and prone to flights of fancy, including "If Elvis Were My Landlord".
 * The three hosts of Top Gear can get like this, especially when they're in one of their competitions and start messing with one another, although Jeremy Clarkson is usually the quickest to start acting like this with the least amount of prompt.
 * Gibson in A.N.T. Farm acts in this way most of the time. He seems to have a mental age below that of the kids - even assuming the ANTs were regular highschoolers, let alone of an age when they'd normally be at middle school.

Newspaper Comics

 * Pig from Pearls Before Swine is eternally clueless and innocent compared to the world around him. All of his friends, particularly his roommate Rat, ridicule him for this.
 * Rat himself can act very childish often, though in a more selfish, bratty way than Pig. An example of this is him separating himself and Pig into a "Cool Fence" and "Uncool Fence". Also, he prefers for people to give him what he wants, despite Goat and Zebra's urging to make him think otherwise.

Radio

 * Wooten Basset from Adventures in Odyssey skirts on this trope. He has many child like interests and behaviors but he also retains a perceptive intellect. It is implied that he acts the way he does out of choice, as his parents raised him to be as strict and disciplinary as possible, not allowed to experience the joys of childhood like playing outside or even having toys.
 * Ray and Ed from the Peacock and Gamble Podcast seem to both have this as their default setting. Ray, in particular, is obsessed with Star Wars lego, and Ed frequently calls him out on the number of bizarre children's toys and memorabilia he has in his house - including a Gamorrean Guard's head, and a full-sized working replica of Gonzo from the Muppets. They both like to speak in a sort of blissful, giddy idiom, too.
 * The BBC's Cabin Pressure gives us Arthur Shappey, steward, who thinks that everything is utterly BRILLIANT.

Theater

 * All the human characters of Miss Bleep (one segment of Rash Acts by Conrad Bishop and Elizabeth Fuller) have regressed to this, having spent an unknown amount of time "trapped in school in perpetuity" with a robotic kindergarten teacher that gives them an electric shock every time they leave or misbehave. Cindy, the resident brown-noser, doesn't even seem to remember the outside world or the fact that she's an adult, and The other two are trying to escape, but they're still jarringly childlike in regard to such subjects as cookies and naptime.
 * Mary in Vanities, mainly due to her difficult childhood. She finally matures in the finale of The Musical.

Video Games
"Alistair (upon pulling out his dollies): "What's that? You want me to be quiet?!""
 * In Ace Attorney, Maya Fey very much fits the bill (even when she is 17 in the first game), most prominently her complete obsession with children's television programs, which Phoenix notes in the 3rd game. The fourth game hints that she hasn't changed in seven years, given that she would be 26 by that time.
 * Also Terry Fawles, who plays it for tragedy when  It's speculated that he may even be mentally hadicapped,.
 * Felicia the Catwoman from Capcom's Darkstalkers saga has been slowly transformed into one of these, as newer games shows her throwing kiddy tantrums, being dense as a brick, losing her head for a piece of food and hanging around with kids like Klonoa (in Namco X Capcom), behaving exactly like him. The creepy/sad/whatever part? Even if she is genuinely friendly and never holds any ill intention, you must remember that she's 28 years old.
 * The original description says catgirls age at about half the speed of a human. Technically, she's 14.
 * The "Child at Heart" perk in Fallout 3.
 * Alistair from Dragon Age. While courageous and noble and all, his main party gifts are action figures. The Feast Day DLC gives him Grey Warden Hand Puppets that you can watch him play with.


 * Possibly Lord Roth from Infinite Space. Well, he is really competent that he becomes one of the top zero-G dogs in the universe, but personality-wise, he fits this trope.
 * Though not actually an adult, Lemmy Koopa from Super Mario Bros. is the second oldest Koopaling, yet he is the smallest Koopaling and dances madly on a circus ball while he shoots magic blasts with a cross-eyed expression.
 * Taizo Hori from Mr. Driller and Dig Dug, is as energetic and dumb as a little kid, he even throws childish tantrums when he doesn't get proper recognition. Quite funny considering he's the oldest of the main cast being 45 years old It's probably the reason why his wife left him.
 * Soul Calibur's Xianghua has a prone move that for all intents and purposes, appears to be a childish tantrum.
 * N of Pokémon Black and White is an instance of this trope being played for tragedy and drama.
 * Any adult Sim on The Sims 3 that has the "Childish" trait will play with toys, get along better with children, hate doing adult things, and like to make faces at people. This trope also counts when it is a Teen or Elder sim.
 * Meredy in Tales of Eternia.
 * Doctor Ivo "Eggman" Robotnik has shown some shades of this throughout the Sonic the Hedgehog games. In spite of his advanced knowledge of science and robotics, Eggman also appears to be very immature and is prone to throwing childish outbursts whenever something doesn't go his way. His television and comic depictions also exhibit some of these traits, most notably his Adventures of Sonic the Hedgehog counterpart.

Visual Novels

 * Scott Pilgrim from the Scott Pilgrim books fits this He's 23 years old and doesn't like taking any adult responsibilities. In fact His roommate Wallace pays for everything even Scott's toothbrush was bought by Wallace. He even dates a 17 year old girl who's more mature then him.
 * Taiga Fujimura in Fate/stay night. This means that she gets kicked out of the route around halfway through each time. Notable childishness: berserker fury over being called Tiger, challenging Saber to a fight and bursting into tears when she loses, the most overboard expressions in the game, switching the labels on soy sauce and oyster juice... actually, it's more difficult to find her being mature.
 * That's usually only within the Emiya household. The VN shows Tiger in a more mature light when it comes to her duties as a teacher.

Web Comics
"Joey: Aww, why do we have to leave? That place was fun! Adam: Because they were going to rape and kill us. Joey: You ruin everything, Adam."
 * A Game of Fools: Joey, in spades:

"Ratfist: Wait. I'm not afraid of that cat! Milt: Hey, neither am I!
 * In the Lighter and Softer Watchmen parody, G-rated Watchmen, the Watchmen characters are given the behavior and personalities of young children. The authority figures are treated as the "grown-ups", despite being around the same age as the main characters.
 * For the God of Lightning and Sky, Volt can act like this at times. Case in point.
 * Ever since his transformation, Ratfist's  has been an embodiment of his id, and will spit out every last thought that crosses his mind, conscious or otherwise. Often this hints that he never really grew up (which may explain why he's prancing about in a costume fighting crime); sometimes the hints are fairly benign ("I want to eat an entire pizza") and sometimes it suggests that kids can be really fucking terrifying.
 * Me neither! Let's eat it!"


 * Jared from Manly Guys Doing Manly Things. Exhibit A: here.
 * Homestuck: It's strongly suggested that Mom Lalonde is like this. That impossibly frilly pink Tastes Like Diabetes bedroom and matching tea set Rose found in the SkaiaNet labs? Almost certainly Mom's.
 * The pets in Housepets consistently have relationships with each other, organize events, and have jobs, and yet still act like children in the context of fun.

Web Animation

 * In Banana-nana-Ninja!, Baninja is a deadly ninja banana with a childlike naivete and curiosity about human society.

Web Original

 * Will from Look a Vlog has elements of this, particularly when interacting with Emily.
 * Rhett and Link have pulled some rather childlike shenanigans. In fact, their entire career is based on acting silly.
 * The author of Hyperbole and a Half according to herself in this entry.
 * The Angry Video Game Nerd (James Rolfe)
 * The Nostalgia Critic is both this and a Psychopathic Manchild.
 * His other alter-ego, Chester A. Bum, is even more qualified for this role.
 * Also, The Nostalgia Chick's My Little Pony episode showed that her best friend Nella still has (and plays with) her my little ponies. Things got dark pretty quickly though, we only see a bit but one is a hooker with a heart of gold, the stranger looking ponies are treated as freakish abominations, and there is at least one death (implied to be a suicide).
 * Most of the Channel Awesome crew fits this to one degree or another. Linkara stands out, given that he collects Power Ranger toys.
 * Much of the cast of Shiny Objects Videos, especially visible in "On The Couch".
 * Mark, the host of Classic Game Room, to the point where he has a separate channel devoted to reviewing toys.

Western Animation
"Dan "Tell me a story..." Elise "There was once a little prince who was so very angry-" Dan "Was his name Dan?""
 * The Fairly OddParents has Timmy's parents, who would rather go out and have fun than take care of Timmy.
 * According to the just-announced Live Action Adaptation, Timmy himself becomes this so he can keep his fairy godparents.
 * On the subject of Butch Hartman shows, Jack Fenton from Danny Phantom.
 * Captain Sunshine from The Venture Bros is a superhero whom is a parody of Batman, everyone thinks he's a pedophile due to the way he acts around young boys as it turns out he's just a big Man Child who's lonely after his first Wonderboy died.
 * Ron Stoppable from Kim Possible, although he might count as an adult teenager. However, he has proven he can be responsible from time to time. In fact it's his innocence and purity that allows him to wield the most powerful sword in the KP world.
 * Dr. Heinz Doofenshmirtz from Phineas and Ferb, who is supposedly in his 40s, but whose mental age seems to be set somewhere between ages 8–10. Even a platypus that wears a hat acts more mature than him.
 * To be fair, the hat-wearing platypus is probably the most mature character in the show.
 * Major Monogram to a much lesser extent can also be this.
 * Lion-O from Thundercats is this very literally. Twelve years old at the start of the journey to Third Earth, he ages another twelve year while in deep hibernation. In consequence, "his body grew, but he did not grow up." He is very literally a boy in a man's body.
 * Dexter's Laboratory: Dexter's Dad & Dexter's Mom portray this often too well.
 * The main characters of My Little Pony: Friendship Is Magic are all responsible, adults (with the possible exception of Pinkie Pie). Their behavior, on the other hand, often ranges from emotionally immature (generally, to set up a lesson in friendship) to downright childish. For example, take the following bon mot from cosmopolitan fashion designer and social climber Rarity, upon hearing that a game of Pin the Tail on the Pony is starting: "Oh, my favorite game! Can I go first? Can I have the purple tail?"
 * Dan on Dan Vs. fits this perfectly, it's even been brought up on the show by his best friend's wife (who finds it endearing).
 * It's gotten to the point where she sometimes treat him as if he were their kid. In "Dan Vs George Washington" she lets him sleep with them (because he couldn't sleep) and proceeds to tell him a bedtime story, much to her husbands' disdain.


 * Moral Orel offers a rather creepy version of this. Doughy's parents, who must be somewhere in their thirties, act, and dress like they're still in High School. This extends to their parenting,(If it could be called that) where they treat Doughy more like an Annoying Younger Sibling, than a son.
 * It's impossible not to laugh when a highly muscled man excitedly tell about how cool his day was while eating cookies.
 * The King from the Spanish cartoon Jelly Jamm possesses no more maturity than his frequent playmate, Rita.