Somebody is working with their head under an object or in a confined space, and they forget where they are. Perhaps they're concentrating on the task at hand, or they're distracted by something else. Then something (often a ringing phone or another person) catches their attention, and they straighten up abruptly, hitting their head. It's a bit like a pratfall on the other end of the body, or a static version of the Low Clearance gag.
Generally, this is Played for Laughs, so the person has a Hard Head and suffers no serious physical injury, though they are quite likely to be sore, flustered or embarrassed. As a result, the person may scold the person who interrupted them, or yell at the ringing phone before answering it. This may also be one way to illustrate that the character is a klutz. On the other hand, the gag may be a way to draw attention to whatever was done or said to cause the person to react this way, or to punctuate the person's surprise.
Common sites for this gag are under furniture or inside a cabinet (say, under the sink in a kitchen or bathroom) and under the open hood/bonnet/trunk lid of a vehicle. May prompt a verbal reaction referring to their new headache. Subtrope to Slapstick and Reaction Shot.
- One Piece: In one of the anime's most hilarious expansions of the manga, when Robin first shows up on the Merry at the end of the Alabasta arc, all of the Strawhats (except Zoro, who's playing Only Sane Man while the others whine about how much they miss Vivi) bang their heads on the ship's railing.
- In Snow White with the Red Hair, the titular heroine hits her head on the underside of a desk after she bends down to pick up a fallen letter and starts to stand up too quickly as she ducks back out from under it when she notices the previously overlooked note on the back.
- In Lucky Luke, this can easily happen to Rantanplan, the stupidest dog in the West. Once, he is taking a nap under a horse watering crate (from which Jolly Jumper is drinking), when he hears Luke telling the saloon tenant to feed his horse and give a bone to his dog... and Rantanplan immediately straightens up at the prospect of food and hits his head. Twice.
Jolly Jumper: [still drinking] Moron...
- Invoked in a 1983 Garfield strip. Garfield ties himself to a lamp and jumps off the table to swing into Odie's face. The dog jumps and hits his head on the table's underside. Garfield sums the scheme up as complicated but Worth It.
- Luann had a Running Gag in the 1990s in which the first panel of a comic features Luann's brother Brad bonking his head on the open bonnet of the car he is trying to fix as his crush, Diane, says "Hi" to him.
- This happens twice in The Cannonball Run, both with the characters working on an engine and hitting their heads on the hood. First, it happens to J.J. when Victor mentions... "Him". Later, it happens to Victor when Blake taps him on the back.
- In Cocaine Bear, Andrew C. Thornton II bails out of his plane by throwing bags of cocaine out the door before preparing his parachute and jumping out... at which point he whacks his head on the door, knocking him unconscious and sending him falling to his death.
- This was a hazard both in and out of universe when filming The Lord of the Rings:
- During the scene in The Fellowship of the Ring where Gandalf visits Bilbo in his hobbit hole, Gandalf, stooping, accidentally backs into a chandelier (as part of the script). His actor Ian McKellen then promptly turns and accidentally smacks his head on the roof, an (unscripted) accident so funny that they left it in.
- In the gag reel for The Fellowship of the Ring, this happens also to the crew. Everyone's sitting inside the hobbit hole listening to directions, then when the meeting ends they all stand up and hit their heads on the roof. Then everyone falls to the floor.
- In Mary Poppins, George Banks is looking in the fireplace for the children's notice for a nanny that he threw there (which Mary has just produced). His wife enters and calls his name, causing him to bang his head on the fireplace. In a scene immediately prior, he had already bumped his head for much the same reason when Mary asked if he'd lost something.
- In Sam, Samantha is hiding under a desk with Margaret when her boss Seymour sticks his head under the desk. Samantha sits up suddenly and bangs her head on the underside of the desk.
- In Scary Movie 3, Cindy comes home to find George passed out at a table. She asks him what happened he says that he doesn't know. He and Cody were playing a fun game when he looked down and...
George: [seeing five dice reading 6 on the table] Oooh, Yahtzee! [stands up and bangs his head on a shelf, passes out]
- In Sleepy Hollow High, Justin is trying to fix his car when he hears Z and Bobbi coming up behind him. He lifts his head suddenly and bangs it on the hood of his car.
- From Star Wars: The Empire Strikes Back, when Yoda tells the ghost of Obi-Wan "Ben" Kenobi that the impatient Luke Skywalker isn't ready to be trained as a Jedi.
Luke: I am ready! Ben, I can be a Jedi! Ben, tell him I'm ready— [bangs his head on Yoda's low ceiling]
- WarGames: When David Lightman visits his programmer friend Jim, Jim has his head under a table. When David says his name, Jim raises his head and bumps it on the table.
- Who Framed Roger Rabbit:
- When hiding in the rotgut room at the bar, Eddie keeps banging his head on the ceiling lamp.
- When Eddie is Caught with Their Pants Down with Jessica (It's Not What It Looks Like), as he pulls up his pants he bumps his head on Jessica's bosom.
- While in Toontown, Eddie bumps his head looking inside Jessica's car, and as Toon Physics are in effect, he gets Circling Birdies around his head.
- In Cheaper by the Dozen, Dad has recently pulled a practical joke on his children, telling them to look in the engine for a bird and then honking the horn loudly. One day when Dad is having to fix the car after a family picnic, one of the younger children sneaks into the car and presses the horn, causing him to hit his head on the hood and burn his wrist on the exhaust pipe.
- Septimus Heap: In Queste, Septimus is so suddenly woken up by Jenna that he does not notice the bunk above and bangs his head on it.
- In The Addams Family episode "Cousin Itt and the Vocational Counselor", Lurch bumps his head on the ceiling of Cousin Itt's room more than once (unsurprising, considering he has to stoop nearly double to move around).
- Agents of S.H.I.E.L.D.: In "Fear and Loathing on the Planet of Kitson", after spending 20 minutes huddled under a gambling table at a casino, when Daisy and Jemma finally decides to move out, they both first clonk their heads under the table. Understandable considering they're still tripping from an alien drug.
- In one episode of The Big Bang Theory, Leonard hits his head while getting something from under the table at a restaurant.
Leonard: Yeah, I'm okay. Hey, did you spill ketchup?
Leonard: I'm not okay!
- Jeff does this in the Community episode "Remedial Chaos Theory" (the episode with multiple timelines). When he's confronted with a problem, he gets up to get a drink and hits his head on a ceiling fan. This ends up happening in every timeline.
- A Running Gag on Home Improvement is that whenever Tim goes to the basement, he always forgets the pipe above the staircase and bonks his head on it.
- M*A*S*H episode "There's Nothing Like a Nurse" sees part of the cast take cover in Henry's office upon hearing an air raid siren. When Radar checks out the window, he reports that the plane in the air is none other than the inept bomber known to the camp as "Five o'Clock Charlie". Henry, hiding beside his own desk, rises to express his outrage only to crack his head on the pull-out panel he frequently uses as a foot rest.
- Occasionally happens to Mr. Conklin on Our Miss Brooks. For example, in one episode he's looking for something under his desk and bumps his head when he gets up.
- Murdoch Mysteries:
- After a seance in "Elementary, My Dear Murdoch", a skeptical Murdoch is on his knees under the seance table looking fruitlessly for mechanical tricks with Arthur Conan Doyle watching him. The psychic enters the room and says, "Have you found the hidden levers, Detect—" He straightens up and hits his head on the table, and the psychic continues, "Oh good heavens, are you all right?" Murdoch rises to his feet and says, "Fine, fine." Doyle is clearly amused, covering a smirk by stroking his mustache.
- In "The Spy Who Came Up to the Cold", Higgins and Crabtree are under a fixture at a murder scene dismantling a piece of equipment and arguing over the disappearance of Crabtree's fancy new pen. As they're trading insults, Murdoch enters and says, "Gentlemen?" to get their attention and inquire about their progress. Both constables straighten up at the same time and hit their heads, effectively ending their tiff for the moment.
- The Red Green Show: Harold's first segment where he's at his new financial advisor job in the city shows him trying to get rid of his gum under his desk. When Red shows up to talk to him, Harold bangs his head on the underside of his desk.
- One Arthur, King of Time and Space space-arc strip had Guevevere complaining that the overhang above her console was dangerous, and she'd bang her head one day. The last panel was a Flash Forward to a couple of decades later, where she does and Arthur concedes she was right.
- Girl Genius: Rakethorn and Violetta are on the lookout during the island arc, Rakethorn hiding in a hole under a rock outcropping. When Violetta calls his attention, he straightens up too fast and bumps his head.
- Rusty and Co.: With Madeline's first appearance, she spots what she believes to be a treasure chest under a table, and reach for it. Except it happens to be Mimic, a Chest Monster, and when Mady finds herself grasping his lip, she hits her head under the table from surprise.
- The Amazing World of Gumball: "The Origins" has Gumball communing with the newly-gotten fish under the kitchen table. It is there that Gumball deduces that the fish is intelligent, at which he jumps for joy. Naturally, Gumball knocks his noggin on the table's underside. When the fish tries to speak to Gumball, the excited kitten is ready to jump for joy again, but this time, dons a helmet before doing so.
- In Captain Pugwash, Jonah is the tallest of the Black Pig's crew and often hits his head on the ceiling of the ship's lower deck.
- In the Darkwing Duck episode "Time and Punishment", Gosalyn is looking around a horrific alternate St. Canard when she happens upon Launchpad fixing a taxi. She calls to him, causing him to spring up (with good reason, because in this St. Canard, neither he nor Darkwing has seen her for twenty years) and strike his head on the undercarriage of the taxi.
- Kim Possible: In one episode, Dr. Drakken tries to escape using a jet pack, forgetting that he's indoors, and slams into the ceiling.
- The Legend of Korra: In Season 3 opener "A Breath of Fresh Air", Mako is sleeping on a cot under his desk at the police station. When his phone ringing suddenly wakes him up, he naturally bumps his head underneath the desk.
- My Little Pony: Friendship is Magic:
- In "Hearthbreakers", Applejack is looking for the obsidian stone Limestone Pie has hidden somewhere in a crystal mine with a low ceiling. She clonks her head from straightening up too fast when Pinkie Pie calls for her attention.
- From "Parental Glideance", in the Wonderbolt lockers room, Rainbow Dash has her head inside her locker when she's startled by her parents showing up, and she clonks her head on the upper shelf.
- Ready Jet Go!:
- In "Sean's Year in Space", on the deck of the treehouse, Sean is lying underneath the fence. When Mindy starts talking to him on the walkie-talkie, Sean gets startled and hits his head on the fence.
- In "Asteroid Belt Space Race", Eggplant looks under Celery's saucer to see her dual custom carbifonators, then bumps her head on it.
- Samurai Jack: The show's last episode (before it got Uncancelled a decade later) has Jack deliberately doing this to make an abandoned baby laugh.
- SheZow: In "Glamageddon", Guy is working on the engine of the Shehicle when he tells Shelia that he intends to blow off Tara's challenge. When Sheila tells him that he cannot, he jerks his up up in shock and slams it into the Shehicle's bonnet.
- Star Trek: Lower Decks: In "Second Contact", when Ensign Tendi asks, "Is there an Ensign Boimler here?", a crouching Boimler forgets that the flap of the replicator he's repairing is open, and he hits his head against it when he stands up.
- A variant of this theme happens with chefs and bakers who work with pizza ovens, or bread-baking ovens where the shelves are spaced closely together and the oven is comparatively deep so that the attendant has to reach deep inside it, even with the handy flat spade to get underneath the pizza tray. It is easy to graze your knuckles on a hot surface whist doing this. The natural reaction when burning the back of your hand on the roof or upper shelf of a hot oven is to snatch it away quickly in the opposite direction. Unfortunately if it's a pizza oven, the floor, or the next shelf down, are inches away — and just as hot. So you then burn the other side of your hand on the floor of the oven and snatch it away in the opposite direction.... Every novice working with this sort of oven does this at least once, to the great amusement of old hands.