Homestar: I let him in. Here you go. [gives the Poopsmith a hamburger, then turns to Strong Bad] Oh, and you're out of mayo. [they leave]
Strong Bad: Is there, like, a sign on my door that says, "Wanted: Everyone I Hate. Inquire Within"?
King of Town: [pops into the frame] I didn't see one.
A neighbor who drops in on a regular basis and mooches around. He or she is often a friend of one of the household kids who is either very annoying or very cute. Because he or she is the neighbors' kid and we never meet his or her parents, he can exhibit all sorts of zany behavior without the need for too much explanation.
In most cases, the main characters have given up on trying to get the drop-in characters to knock, a la Kramer from Seinfeld, or Lenny and Squiggy on Laverne & Shirley. Considering how much of a pain in the rear this sort of drop-in tends to be, the viewer is sure to wonder whether the host has ever thought to just lock the door, but don't expect that to be addressed in the show. It's exceptionally rare to even see a lampshade hung here. Sometimes the drop-in character's arrival is presaged by an ironic foreshadowing — see Inadvertent Entrance Cue.
- This commonly happens in harem series, mostly just to result in Not What It Looks Like moments.
- Miu from Strawberry Marshmallow drops in by Nobue and Chika by jumping the roofs of their adjacent houses and climbing in through Nobue's bedroom window. She even does this in the middle of the night to sit on Chika's stomach, for no other reason than to be the Jerkass she always is. Heck, she even drops in through the window when the crew are staying at a hotel, purely out of force of habit.
- Renge Houshakuji from Ouran High School Host Club has entrances that are more dramatic than most drop-in characters, sometimes rising out of the floor on a pillar.
- Yotsuba&! is the extremely cute example of this trope. She doesn't distinguish much between her own house and her neighbor's house and even calls the next door neighbor mom "Mom" just like her own kids do.
- Vanessa in Madlax starts out this way.
- Lucy from Fairy Tail is an inversion; she's the one that gets dropped in on... constantly... by everyone. People make themselves so comfortable at her house it's ridiculous.
- Ikkyu, Nozomu's "one day friend" in Sayonara, Zetsubou-Sensei sometimes plays this role, with the twist that he doesn't drop in at Nozomu's home, but rather at the school Nozomu nominally teaches at, which makes him a more bizarre example, as does the fact that he isn't really a close friend of the protagonist. Lampshaded once by Nozomu, who asks him "Why are you here? What is it you do at this school again?"
- Almost every major character has played this role at least once. Many a chapter or episode has started either with Itoshiki at home when his students suddenly barge in, or one of his students (usually Nami) at home when Itoshiki, who just happens to be passing by, overhears them saying something that causes him to barge in and launch into one of his rants. The biggest exception is Matoi, who doesn't drop-in because she was already there all along.
- Most of the other tenants of the titular Maison Ikkoku force their way into Godai's small apartment room when they feel up for a bit of a drunken party. He does try locking people out, but it doesn't work very well, particularly Yotsuya-san who just breaks holes in Godai's wall when he does (so he can cross the room and peep at Akemi next door through a peep hole in Godai's closet).
- The insurance salesman Jolyon Wagg from Tintin.
- The vacuum cleaner salesman Theofiel Boemerang in Suske en Wiske who also refuses to go away unless people buy his stuff.
- Nero: The mad pirate Abraham Tuizentfloot also frequently drops by at Nero's house to attack him and everything with his sword. Sometimes he just jumps in through the window!
- De Kiekeboes: Fernand Goegebuer, Kiekeboe's neighbour from past the street, also has the tendency to drop by without knocking or walks in during awkward situations.
- The Pieces Lie Where They Fell: Downplayed with Reel, AKA Kamen Rider Skull II - he only shows up a few times, and they're all in alternate-continuity versions of the Pieces-verse (published as omakes).
- The Room: Because 90% of the film takes place in the same open-floor apartment, additional characters tend to drop by to progress the plot.
- The Goldbergs was recognized as the Trope Codifier by many, including Roger Ebert in his review of the documentary about the series.
- Eddie Haskell on Leave It to Beaver.
- The Golden Girls: Stanley Zbornak, ex-husband of lead character Dorothy Zbornak (Bea Arthur), often dropped by — usually unannounced — to try to win Dorothy back.
- In Friends, every character does this at one time or another, usually at least once an episode.
Ross: WE HAVE GOT TO START LOCKING THAT DOOR!
- Slightly lampshaded at one point near the end of the series when Monica can't remember the last time her apartment door was locked.
- Also lampshaded when Ross is about to finally tell Rachel he loves her, but is interrupted by ex-fiancee Barry bursting in the door and beating him to the punch.
Monica: "Ok, here's your key, now you've got to christen it! Now go out and come back in!"
- Lampshaded again when Monica and Chandler - who have lived across the hall from each other since before the show began - decide to move in together, and she gives him a key. Even better; the key promptly breaks in the lock because it hasn't been used for so long.
Chandler: "Door hasn't been locked in five years, but ok!"
Monica: Hello, people who do not live here! I gave you a key for emergencies.
- This is also mentioned by Monica, in episode 3.19, when she enters her house only to find Phoebe, Chandler and Ross there.
Phoebe: We were out of Doritos.
- Combined with lampshading for their Limited Social Circle, in season 6, when they're all in the apartment and someone knocks on their door. The whole gang look at each other in astonishment for a good few seconds, clearly wondering who the hell was was knocking to come in.
- And again in the last episode, where Monica and Chandler, about to leave their apartment for good, solemnly drop their keys in a dish for the landlord to pick up - followed by all the other leads adding their own key to the dish.
- Howard on The Bob Newhart Show was a classic Drop In Character, often having just flown in or about to fly out.
- Nick at Nite once ran a campaign including multiple clips of Howard asking "what's for dinner?"
- On Newhart, this role was filled by Larry, Darryl, and Darryl.
- Lenny and Squiggy on Laverne & Shirley.
- On Happy Days the Fonz was originally a Drop In Character before ascending to Breakout Character status, while later on Fonz was himself dropped in on by Chachi.
- Also on Happy Days: Potsie, Ralph Malph, Lori Beth, Arnold, Al Delvecchio, Jenny Picalo, Roger Phillips, Melvin Belvin, Pinky Tuscadero, Officer Kirk...pretty much every character on the show who wasn't a member of the Cunningham family wound up crossing their threshold uninvited at least once.
- Spoofed in at least one of Cracked magazine's "Happy Daze" parody comics, as illustrated above.
- Fonzie was justified in that he was lodging with the Cunninghams in an attic apartment. He does tend to stretch the boundary between lodger and family member quite a bit however.
- Seinfeld: Kramer, George, and Elaine are all drop-in characters because they tend to arrive at Jerry's apartment unannounced. Kramer is the best fit because he lives across the hall and doesn't even need to be buzzed up. He simply bursts through the door without warning. In one episode, Jerry actually had the door locked for an unrelated reason, leading to a loud crash as Kramer tried to perform his trademark slide.
Jerry: She likes the pop-in. I've told her how I hate the pop-in. (Pointing to George.) He likes the pop-in too!George: Just popped in now, I'm a big pop-in guy. How 'bout Kramer?Jerry: Oh, HUGE pop-in guy!
- Family Ties has several of these — Skippy was the nerdy one, Nick was the punk one (well, TV-punk).
- "Bud", "Cockroach" and several of Vanessa's friends on The Cosby Show.
- The Australian sitcom Hey Dad..! had several drop in characters over the years, most famously "Nudge". Inexplicably, one of the drop in characters, Ben, ended up moving into the family proper.
- Family Matters: Steve Urkel is the weird nerdy kid from next door who exhibits zany behavior and drives Mr Winslow nuts. Although he takes over the show, episodes tend to feature the Winslow household primarily, and Mr Winslow (a police officer) tries to get him tossed out multiple times, instead of locking his door.
- On Frasier, Niles was always just dropping by, though reasonable explanations were often given, usually involving Maris and her friends doing something that drove him out of his own house.
- Six LeMeure on Blossom is a rare female Drop-In Character.
- Steve and Marcy, and later Jefferson and Marcy on Married... with Children.
- Ed Norton, from The Honeymooners
- In the British sitcom Birds of a Feather, the drop-in character, when faced with a locked door, smashed a window to get in while the main characters watched.
- Good Times: Willona's apartment is rarely seen, like when she adopted a young Janet Jackson.
- Inverted in Keeping Up Appearances, in which the main character, Hyacinth, forcibly drags Elizabeth, her neighbor, into Hyacinth's house and forces tea on her. Usually in Royal Doulton teacups (...with the hand-painted periwinkles...). The fear of dropping these teacups has turned Elizabeth into an agoraphobic wreck.
- Charley Dietz from Empty Nest would frequently drop into Harry's kitchen just to raid his fridge and hit on his daughters.
- Hakeem Campbell on Moesha. All of his meals appear to come from the Mitchell household ("My favorite cook!" "Your only cook!").
- Lampshaded in the Coupling season 4 episode 'Nightlines' in which one of the characters barges into the home of another (due to her retaining the front door keys of anyone she's ever had a relationship with) which causes another to state that she has to stop doing that because 'this is not, repeat: not an American Sitcom'.
- The Fresh Prince of Bel-Air has Jazz, who's both a "drop-in" and "throw-out" character.
- Raymond's parents in Everybody Loves Raymond are constantly dropping into his home without notice. Such unwanted behavior even makes it into the musical introduction.
- Iola Boylan on Mama's Family. She never knocks, but her Catchphrase (always said after she enters) is "knock, knock."
- Maynard G. Krebs on The Many Loves of Dobie Gillis.
- Pretty much the entire teenage cast of That '70s Show with regards to the Foremans' house, particularly the basement (though naturally they have no problem wandering about the rest of the house and enacting other elements of the trope, such as mooching food and pilfering Red's beer). Occasionally lampshaded, such as one time when Kitty mentions an embarrassing secret of Eric's aloud.
- Eric: Mom! Be careful. At any given time, there are at least 3 individuals in this house that would use that information to destroy me.
- Lampshaded again in one episode where Eric, Hyde, and Laurie are all grounded. Red goes around to perform a "bed check", with Eric having Donna in his room, Hyde having Jackie, and Laurie with Kelso. Then, Red goes down to the basement, where Jackie, Fez, and Kelso are sitting watching TV, like nothing is wrong.
- Martin had a character simply referred to as "Brother Man", who occasionally invited himself into Martin's apartment through his window.
- Reba featured possibly the worst example of this trope, as Reba's ex-husband and the woman he left her for felt perfectly justified in walking into her home without any form of notice or even knocking. It costs too much effort for Reba to change locks all the time just to keep them out, and plots advance faster without doors locked.
- She did lock the door occasionally, but only for gags (though I believe one had Barbra Jean refusing to give up).
- Clarissa's friend Sam on Clarissa Explains It All. He didn't even bother to use the door when he dropped in: he used a ladder to climb through Clarissa's bedroom window. As well, he had his own musical sting.
- Likewise, Morgan in Chuck often uses the "Morgan Door" - Chuck's window.
- Kimmy Gibbler in Full House.
Kimmy: Hey, guys!
Stephanie: Gibbler, don't you ever knock?
Kimmy: I used to, but no one ever let me in.
- Roger in Sister, Sister.
Tia and Tamara: "Go home, Roger!"
- Mo from Smart Guy.
- In Kenan & Kel, we never see Kel's home or family, while much of the action takes place at Kenan's home and his parents and sister are relatively major characters. Kel also hangs around Kenan's place of work, Rigby's. This is even parodied in a certain episode, in which a letter addressed to Kel is delivered to Kenan's house as if Kel lived there.
- In The Sarah Jane Adventures Maria's parents are divorced and she lives with her father; her mum frequently drops in unannounced.
- Bernard "Beans" Aranguren, in Even Stevens. He was essentially a parody of the Drop-In Character, since the Stevens family couldn't keep him out of their house no matter what they did. And not only were his parents never seen, but the only episode where anyone tries to track Beans back to his house led two of the main characters to conclude that Beans was in fact an alien.
- Carly's friends Sam and Freddie from iCarly, or as Spencer calles them, "her two friends who never hang out at their own homes." The show tended to lampshaded their constant presence, such as when Freddy barged in saying "Hey, mind if I come in, 'kay thanks!"
- Being a recurring side character, Freddie's mom is a classic example of the trope.
- At one point Spencer mentions he almost didn't recognize Sam and Freddy since they weren't sitting on his couch.
- It should be noted that due to Sam's skills with a lockpick, locking the door on her is pretty much useless.
- Monroe Ficus was this in Too Close for Comfort, generally when he appeared, it was obvious that he was going to say or do something that would irritate Henry Rush. Eventually when the show became a first-run syndicated series, he would become a live-in character, when he moved into a third floor addition of the Rush house, after his apartment is torn down. By the time the series was rechristened as The Ted Knight Show for its final season, he reverted back to being a drop-in character when the Rushes moved from San Francisco to nearby Marin County.
- Rose from Two and a Half Men?
- Maxine Shaw from Living Single.
- Kenny from The War at Home. We do see his parents, though. He even lives with the Golds for a while, after his parents have kicked him out for being gay.
- That's My Bush! brilliantly spoofs the drop-in character by having him drop into the White House.
- The Big Bang Theory:
- Howard, Bernadette and Amy are usually invited over for a real reason like Vintage Video Game Night. Penny, on the other hand, once came over in her pajamas muttering "Out of coffee, need coffee" and proceeded to pour herself a cup like it was nothing.
- In the early seasons Penny was often lampshaded as taking advantage of Leonard's need for female companionship (even if unintentionally), and in later seasons she was Leonard's girlfriend, and so it made sense for her to be able to pop in whenever (many serious relationships involve each partner giving the other one a copy of their key).
- When Leonard was dating Priya, she thought it was odd that Penny would always just walk into the apartment in her underwear (pajama's).
- Toma Lá, Dá Cá: Landlord D. Álvara, who began to appear every time someone spoke her name (to the point that the characters tried to stop utterances of it).
- Aunt Jackie from Roseanne neatly solved the question of why she's not locked out by being the title character's sister. An entire first season episode explored Dan's irritation with her status as this.
- Community: Dean Pelton often does this to the study group, and one episode shows he eavesdrops on the group so he'll know the best time to barge in.
Jeff: We were debating how many times a year a man can drop in a study room in a dumb costume with irrelevant news.
- Pretty much the entire cast of Sanford and Son other than the title characters were this with Esther, Grady and Bubba being the most frequent offenders.
- Mozzie from White Collar. Neal so regularly comes home to find Mozzie at his home that he doesn't even bat an eye, and plenty of cracks are made about Mozzie depleting Neal's large supply of fine wine.
- Buffy the Vampire Slayer. Spike once he became allied with the Scoobies in Seasons 4 and 5.
- Fred and Ethel Mertz on I Love Lucy, either through the front door, or through the balcony door next to the kitchen.
- On Sesame Street, Ernie or Bert can expect any of the lovable monsters to drop in for a chat and an exercise or lesson.
- On Wizards of Waverly Place since a lot of the plot takes place in the sub shop, it's easy for characters to 'drop in'. Harper was this until she actually started living with the Russos.
- Shawn on Boy Meets World, generally through the back kitchen door or Cory's bedroom window via a tree in the backyard. It's been vaguely implied from time to time that he does so to escape violence and hostility in the trailer park, or because he doesn't have enough food to eat at home. Gradually lessens as he grows up.
- Not Mr. Feeny as often as one would think, but that's only because he's usually content to talk over the garden fence: he takes to this trope quite heartily in one episode when the Matthews', for once in their life, don't go to bug him for advice with a problem, resulting in him barging in in the middle of the night, accusing them of keeping him up worrying.
- On Welcome Back, Kotter, the Sweathogs frequently dropped in on their favorite teacher, via Enter Stage Window.
- On Max & Shred, Howie rarely knocks and Alvin even has a button that automatically opens his bedroom window, which Howie uses frequently.
- On Madam Secretary, White House Chief of Staff Russell Jackson is constantly dropping by Secretary McCord's office unannounced (aside from a few seconds' warning provided by her staffers).
- In Its Not Easy, the female lead's ex-husband walks into her house — across the street from his — seemingly whenever the mood strikes him.
- Profesor Jirafales in El Chavo del ocho is the only member of the main cast that is not a resident in Vecindad nor the owner, he gets there in every episode to visit his Love Interest Doña Florinda. Señor Barriga and his son Ñoño to some extent could be counted too but Señor Barriga as the owner of the building collecting the rent has a reason to be there.
- The noisy neighbor Zoila visits Chaparron and Lucas house in every sketch of Los Chifladitos [The Little Stooges] in Chespirito asking for a sugar cup, never discovering that her neighbors are lunatics.
- Cousin It in The Addams Family, the most common visitor of the family. Even his luggage is part of his iconic look.
- Out of This World (1987): Garland household apparently has an open-door policy for neighbors, family members, and local government officials.
- Elmo, the neighborhood kid who often drops in on Blondie's Dagwood, usually while he's trying to nap. On at least one occasion this was lampshaded by Dagwood saying, "I've got to put a lock on that front door."
- Nermal became this in Garfield after his origin was retconned (he originally belonged to Jon's parents).
- Get Fuzzy has Bucky's British cousin Mac Manc McManx (or "M3"), who has been squatting in Rob's flat for years, much to Bucky's discontent.
- Dennis the Menace (US): Dennis would frequently visit unannounced (and unwelcomed) with crotchety neighbor Mr. Wilson.
- Sally Forth (Howard): Faye, the best friend of the Forths' daughter Hillary, often pops up at odd times, and the strip will lampshade this by having Sally or Ted sarcastically ask whether she's moved in with them.
- In the Big Finish Doctor Who story "The Maltese Penguin", the Doctor acts as one of these, bursting in ostentatiously at key points of the story begging Frobisher to come back and travel with him. Frobisher constantly rejects him (at one point, when Frobisher is about to be murdered, the Doctor shows up to save him, and Frobisher tells him to go away) but it's also explained that Frobisher feels rather bad about treating the Doctor like that.
- On Fibber McGee and Molly, almost every supporting character fit this trope. In practically every episode, a succession of them would drop in at 79 Wistful Vista to chew the fat with the Mc Gees.
- Half the cast of the Touhou series make a habit of dropping in at the main character's residence unannounced and mooching around. The worst offender is probably Yukari, the Teleport In Character. In the games, the player character serves this function, especially in the fighting games. Drops in, fights, leaves. After beating up everyone, they FINALLY find the real culprit!
- A Sim with 10 Outgoing points in The Sims 2 will do this if your controllable sims make friends with him. You can still lock your door, though.
- Girl Genius: Jenka is a scout and Da Boyz direct superior who shows up every once in a while, with very little fore warning of her appearances.
- In Questionable Content's early days, Hannelore has a habit of showing up uninvited in Marten's apartment at odd times, possibly because as her downstairs neighbor, he's convenient, and she doesn't initially have anyone else to visit or talk to. She'd sometimes be asleep on his couch due to her sleep problems. Lampshaded hilariously at one point when Marten needs to talk to someone, goes home to talk to Hannelore, and then:
Marten: ... Wait. How'd I know you'd be in my apartment?
Hannelore: Wait, why am I in your apartment?
- In Something*Positive, Mike had a habit of entering Davan's house uninvited and raiding the fridge for whatever Davan had cooked "without ever offering me any or wondering if I'd made it for some specific non-Mike-related purpose".
- Stand Still, Stay Silent: Reynir is most likely becoming this from Onni's point of view. Reynir, thanks to Wrong Context Magic, can simply walk into Onni's protected area in the mage-exclusive dreamspace like its protections don't exist. Onni, being quite far away from the crew in the real world, tolerated Reynir's accidental first visit in his area to get news about Tuuri once he realized Reynir was travelling with her. Some time later, Reynir wants to check out a strange location in the dreamspace but wants company doing it, so he goes to Onni's area to ask him to come with him, prompting Onni to hint that he actually doesn't want Reynir to come visit him there again. The following time Reynir shows up univited in Onni's area, he gets tolerated once again because it's an emergency and Reynir is telling Onni about the troll Zerg Rush about to overrun the crew on the off-chance he can help with it. Onni is able to help long-distance, but it leaves him in Deep Sleep in the real world, which prompts Reynir to go check on him in the dreamspace. On that occasion, Onni asks Reynir whether or not Reynir took the hint he gave him on his second visit, only to have Reynir point out that Onni has never actually told him to not come back.
- Wilde Life: Clifford is extremely persistent about doing this to Oscar, given that during the brief time for which Oscar didn't want Clifford in his house, he had to lock his bathroom window rather than his door. Before that incident, Oscar had once come home to Clifford playing cards with Sylvia, the ghost haunting his house.
- In The World of Vicki Fox, Jerkass Zephy has a habit of showing up at Vicki's place unannounced whenever her latest boyfriend kicks her out.
- In The Lizzie Bennet Diaries, about everyone but Lizzie and Charlotte.
- The Nostalgia Chick: Nella became an Ensemble Dark Horse and started appearing in nearly every video.
- Atop the Fourth Wall: '90s Kid just appears out of nowhere in numerous episodes. Sometimes, other people actually talk back to him. This is lampshaded in the "Blackest Night" crossover with Spoony:
Spoony: Who the fuck is that?!
Linkara: Oh, just ignore him. He's like a pop-up ad, he won't go away.
- Warning! Readers Advisory! has a handful: mad scientist supervillain Herr Doktor Innis du par Nachteltaffen, Friendly Neighborhood Vampire Nachzehrer, Lethal Chef Red Chef, and a surprisingly affable Cthulhu.
- The first season of Pretty Dudes has Eagle as this, though she's often seen bringing over tequila or offering dinner rather than taking, borrowing or mooching anything.
- Played for Laughs on The Simpsons: Nelson Muntz is known to show up out of nowhere, point at a character, shout "Haw, haw!" and then leave.
- Inverted on Aqua Teen Hunger Force, where the main characters are the ones who are always dropping in at the weird next-door neighbor Carl's house — usually to use his swimming pool without permission. In one episode, he builds a laser grid around his house to keep them out. Naturally, the results are less than optimal...
- Ron Stoppable is pretty much this, almost never seen at his own house, he's even there when the Romantic False Lead is hanging out with Kim Possible during The Movie. On the occasions when he is seen at his own house, it usually foreshadows an event of real significance, such as an impending move to Norway or the acquisition of an adopted sister (none of which his parents ever tell him about in advance).
- Foster's Home for Imaginary Friends has Goo and Cheese, with an episode for each centered on keeping them out of the titular Home. Of course, it doesn't work.
- My Little Pony: Friendship Is Magic: Though an Ensemble Cast, whoever is the central character of the episode in question will frequently find themselves badgered by uninvited guests. Aloof Grumpy Bear Twilight Sparkle is naturally the most frequent victim to this, most often from Pinkie Pie (who has a tendency to bring a party load of other characters along with her) and Rainbow Dash, who often crashes into someone's house. Rainbow Dash barged into Fluttershy's house at night in one episode for the purpose of dragging her out of bed.
- Bojack Horseman: As a parody of inane 90s sitcoms, the presence of a character like this is de rigeur in show-within-a-show Horsin' Around. Named "Goober," he is apparently the Phrase Catcher for the Catchphrase "Go home, Goober!"
- Richie in Static Shock often just showed up at the Hawkins' house in early episodes. This eventually gets Lampshaded by Sharon and then Played for Drama when it's revealed the reason he didn't want Virgil coming to his house was because his father was racist.
- Fu-fu on Sagwa, the Chinese Siamese Cat is one of these.
- On several occasions, Pretty, Eugly and Olaf from Kaeloo just randomly show up in the middle of an episode and join the main four in whatever they're doing.
- Gusto in Adventures of the Gummi Bears is the only bear that does not live in Gummi Glen; he has his own house inside of a waterfall. He visit the rest of the Gummies often, though. Cavin the Token Human is another example of a frequent visitor.