History Main / ItsACostumePartyISwear

This trope may result in AnAesop about trying to get InWithTheInCrowd. See also UnderdressedForTheOccasion, which can occasionally result from a similar prank. Compare UninvitedToTheParty, where they're so uncool they're not invited, period. Not generally related to ForHalloweenIAmGoingAsMyself and tropes related to that.

* Inverted on ''Series/HomeImprovement''. Randy's girlfriend decides they're going to a costume party as Raggedy Ann and Andy. But then she gets mad at him over a minor matter...and shows up in street clothes, making his lame outfit look even lamer.

* In the ''Series/{{Castle}}'' episode "The Good, The Bad & The Baby", Castle tells Beckett that his family has a tradition to wear costumes for Thanksgiving. She shows up to dinner in a costume... but she's also suspicious enough about the whole thing to bring one for him as well.

%% Image selected via crowner in the Image Suggestion thread: https://tvtropes.org/pmwiki/crowner.php/ImagePickin/ImageSuggestions87
%% Please do not change or remove without starting a new thread.

* An ad for salsa has Jean-Claude Van Damme enumerating the types of salsa, said types being consumed by someone whose appearance epitomizes the flavor: hot (sexy guy); mild (frumpy woman) and garlic (guy in a vampire costume, who says "I thought it was a costume party!")

* An ad for Doritos, features a guy at a party dressed like Dracula, saying he thought it was a costume party.

* Johnny Storm pulls this on Ben Grimm in an issue of ''ComicBook/UltimateFantasticFour''. Despite the thorough humiliation of showing up at a fancy party dressed as Carmen Miranda when he's already a gigantic rock-skinned thing, Grimm hooks up with Alicia Masters shortly afterward. Before getting over the prank and meeting Alicia, he reveals that he's tried and failed to kill himself due to his invulnerability and wonders if Reed can find a way to kill him. Then they try to time travel to undo his origin story. Johnny's prank tore open a still fresh wound.

* One WesternAnimation/DonaldDuck comic has Gladstone Gander trick Donald into believing the ball he and Daisy will attend is a costume party, and that Daisy wants him to dress up like a gnome (in hopes that Daisy, when seeing Donald in costume, would be so ashamed of him that she would ditch him in favor of Gladstone). Unfortunately for him, Daisy finds out and to simultaneously get back at him and make Donald feel less ridiculous, she TOO shows up in a gnome costume.

* A variation of this occurred in a ''ComicStrip/DennisTheMenaceUK'' strip in ''ComicBook/TheBeano'' where Dennis convinced Walter it was dressed up as RolfHarris day at school. This was considered one of the former Beano editor's all-time favourite strips and was reprinted in The History of the Beano.

* The AlphaBitch character successfully pulled this on Amanda Bynes in ''Film/WhatAGirlWants''. In that case, the heroine was told to dress informally for a very formal event - in this case a fashion show. This backfires on Clarissa however when Daphne's casual outfit leads people to assume she's one of the models, and she's put on stage - where she steals the show.

* Literature/BridgetJones, protagonist of that movie, goes to a party that she thinks is a "Tarts and Vicars" party, as a PlayboyBunny. In this case, she's not alone at least; her father arrived dressed as a vicar, another guest arrived in a more elaborate bishop costume, and the only other "tart" hides in a nearby hedge until she can make a quick getaway while no one is looking. It's made clear that the party ''was'' a "Tarts and Vicars" party, but that the organizers changed their minds and failed to inform Bridget or her father.
* Occurs to the king of France in the movie ''Film/StartTheRevolutionWithoutMe''. His wife (who isn't too crazy about him) originally told him that a reception was going to be a costume ball, then she changed her mind without telling him. Cue scene where the already socially awkward king arrives dressed in a ridiculous rooster costume, apologizing profusely to everyone within earshot.
* ''Film/GroundhogDay'' has a variation of this, with Phil's movie date showing up in a skimpy FrenchMaid outfit and saying, "I thought we were going to a costume party!"; however, Phil joins in the gag himself by dressing up as Clint Eastwood's "[[Film/DollarsTrilogy Man with No Name]]" character.
* Played with in ''Film/TheFinal''. The outcasts tell all of the popular kids that they are holding a costume party, and when they arrive, they get drugged and [[ColdBloodedTorture tortured]] as payback for years of abuse. The "costume" part was so that the outcasts could conceal their identities until it was time to strike.

* One of the supporting characters in ''Film/IWasATeenageWerewolf'' is tricked by her devoted but prank-loving boyfriend into showing up at a party in costume.
* A variant happens in ''Angus, Thongs and Perfect Snogging'', the film adaptation of the ''Literature/ConfessionsOfGeorgiaNicolson'' series. Georgia attends a party dressed as a cocktail olive only to find that everyone else at the party is wearing much sexier costumes ({{Cat Girl}}s, fairy wings and so on), including her friends who were supposed to dress as food with her but changed their plans at the last minute. Georgia looks comically out of place and runs home in embarrassment. In the book, she mentions that she regrets dressing as an olive at a party, but [[NoodleIncident doesn't go into detail about what happened]]. The implication is that Georgia and her friends expected everyone else to dress stereotypically so they had planned to dress as food to be different. Georgia just missed the memo when the other girls changed their minds.

* It happens to Chevy Chase in the 1995 movie ''Man Of The House''. Jonathan Taylor Thomas tells him to wear full Native American regalia to an Indian Guide barbecue. The barbecue is, of course, a casual event, and the other tribe dads have to tell Chevy that the Indian garb is better suited for formal tribe events.

* A variant in ''Film/LetsBeCops''. Ryan invites Justin to a costume party, and they wear their fake police uniforms, only to find out everyone else is wearing formal attire with fancy masks. Ryan had never learned the difference between a "masquerade" and a "costume party".

* ‘’Literature/AccidentalDetectives’’: Mike and Ricky are best friends but they do enjoy pranking each other, and the only prank Ricky holds a grudge for is Mike using this trope to get him to dress like a banana for the (formal) birthday part of the prettiest girl in their class.

* In Barbara Wersba's ''The Dream Watcher'' a dance called the "Tramp's Ball" was held at Albert's school and he assumed that it would be a costume party. He showed up dressed as a fairly convincing tramp, only to discover that all of the other boys were wearing shirts and old jeans, while the girls had on pantsuits.

[[folder:Puppet Shows]]
* [[InvertedTrope Inverted]] in the ''Series/UnderTheUmbrellaTree'' episode "Holly Gets the Blues." Holly accidentally falls face-first into a tub of blue fabric dye just hours before she's supposed to go to a party, and though she manages to wash the dye off her face in time, she can't get it out of her hair. But then she learns that the party is a costume party, so she goes after all, dressed as a blue-haired clown.
[[/folder]]

* Once on ''Radio/TheJackBennyProgram'', Phil Harris found out Dennis Day could do a dead-on impression of Ronald Colman, Jack's next door neighbor. He talked Dennis into calling Jack (as Ronald Colman) and asking Jack to come to a costume party at his house. The next night, the Colmans are getting ready to go to bed, when they hear a knock at the door. They answer, and Jack bursts in dressed as a cowboy. The Colmans are completely bewildered.

* Done very well in the musical adaptation of ''Theatre/LegallyBlonde''. Elle is called a skank by her romantic rival for her PlayboyBunny costume. She recovers by taking someone's glasses and insisting she is dressed as an undercover Gloria Steinem and asks her rival, loudly, if she is calling Gloria Steinem a skank. A horde of feminists descend upon the rival as the victim leaves.

* Subverted in ''Webcomic/{{Homestuck}}'' during the Ministrife. Porrim thinks it's this, but Vriska [[InsistentTerminology keeps saying it's a fight]] while an entire ghost army collides.

* [[InvertedTrope Inverted]] in an episode of ''WesternAnimation/{{Doug}}''. Doug is invited to a party at Beebe's house and ends up with a large pimple on his nose right before. The entire episode plays on his attempts to get rid of it and his embarrassment. When he finally sums up the courage to go, Skeeter informs him that is actually ''is'' a costume party, allowing him to wear a mask to cover it up.
* A partially subverted version is played out in ''WesternAnimation/DannyPhantom'' when Danny finally gets invited to a popular party at Dash's house. He is told that everyone has to wear expensive sweats. After selling a bunch of his dad's old junk to earn cash to buy the clothes, he turns up only to find that the actual dress code is "geek chic". So everybody is actually dressed like Danny and his "loser" friends, not because Dash wanted to make fun of him, but because Dash didn't have the money to buy his own expensive sweats--having spent his last dollars on, ironically, Danny's garage sale. It's open to debate if Dash wanted to make fun of Danny or not. Dash's change of plans was emailed to the other invitees and he claimed to have forgotten Danny wasn't in the group of people who received the email.
* A ''WesternAnimation/TheWeekenders'' plot involves Tino and Tish being invited to an alleged costume party. They mention nothing to Lor or Carver, thinking their feelings will be hurt because they weren't invited. At the end of the episode, Lor and Carver (who ''were'' invited, actually, and knew that the party wasn't a costume party) tell Tino and Tish that they could have cleared up matters if they'd known Tino and Tish had been invited ([[FridgeLogic never mind that they never mentioned their own invitations.]])

* In ''WesternAnimation/SabrinaTheAnimatedSeries'' Gem invites Sabrina to a ball at her house and tells her the theme is country and western. Sabrina casts a spell to give herself an authentic costume and shows up to find out it was a formal ball. Perhaps in a bit of irony, before she casts the spell, she pulls out a red evening gown wondering if it's appropriate for a country and western party. If she had worn that outfit, Gem's plan might have backfired.
* ''WesternAnimation/GarfieldAndFriends'' episode "Top Ten" featured Garfield announcing some {{Top Ten List}}s. One of them was a list of ten reasons Jon's dates ended [[CasanovaWannabe in a bad way]]. One of the items in the list was Jon forgetting to check which kind of party he's invited to. As an example, the viewers were treated to a clip of Jon arriving at a party wearing a chicken costume while the others are normally dressed. Jon started arguing about what the invitation stated.
* Harry accidentally does this to himself in a ''WesternAnimation/{{Cyberchase}} For Real'' segment. His friend gave him a coded note in a Viking rune cipher, and Harry translated the first part telling about the time, but only translated up to "Co" on the last bit and assumed that the rest meant "Costume Party" based on how long the words were. He arrived at his friend's house dressed in a homemade Viking outfit, only to have his friend correct him saying the note read "Concert Start".

* In the WesternAnimation/DuckDodgers episode "That's Lifomatica" Dodgers invites his friends (and enemies) to a party to show off his Lifomatica system and Commander X-2 is shown in the middle of the party dressed as Little Bo Peep.

* Inverted ''twice'' on ''Series/{{Cheers}}''. The first time was when [[CheersS1E7FriendsRomansAccountants Norm organized an office toga party]] and the second was when Rebecca asked everyone to dress in 19th century attire for the bar's centennial. In both cases, the organizer is the only one who dresses up.

* Inverted ''twice'' on ''Series/{{Cheers}}''. The first time was when [[Recap/CheersS1E7 Norm organized an office toga party]] and the second was when Rebecca asked everyone to dress in 19th century attire for the bar's centennial. In both cases, the organizer is the only one who dresses up.

* One of the first things Morpheus does in ''ComicBook/TheSandman'' after escaping from his confinement is to grab nourishment from a passing dream -- in this case, a dream where a man's gone to a glamorous party populated by celebrities dressed as a clown.

[[folder: Puppet Shows]]

* One of the ''Literature/HorribleHistories'' books has a section on [[https://en.wikipedia.org/wiki/John_Bingham,_7th_Earl_of_Lucan Lord Lucan]], which discusses his attempts to [[{{Gaslighting}} gaslight]] his wife and get her certified as insane. A picture accompanying this section has Lady Lucan dressed in a chicken costume and shouting "But I was told it was fancy dress!" to a room of normally-dressed, bemused-looking partygoers, as Lord Lucan whispers to one of them "See what I mane? Nutty as a fruitcake."

* This happened to actor/comedian Alan Davies one year at the British Comedy Awards. The invite claimed that the event was to feature a "Latin theme" and encouraged the creative industry types to show their flavour. Cue Alan dressing up as a matador, only to discover he was the only person in costume. On live television. He talks about the experience [[https://www.youtube.com/watch?v=q42sKMS1M48 here]].

* A non-malicious example in ''Webcomic/WhatsUpBeanie'': Beanie misinterpreted 'dress-up party' as a costume party and demands to be a pink cat. Beanie's mother makes it work anyway.

* In ''Film/LegallyBlonde'', Elle is invited to a costume party by Vivian and comes dressed as a Playboy Bunny among casually dressed college kids. Elle manages to work it anyway, but it is also this scene which finally convinces Elle that Warner is never going to take her seriously, which gets her pissed and gets her motivated to succeed.

* A partially subverted version is played out in ''WesternAnimation/DannyPhantom'' when Danny finally gets invited to a popular party at Dash's house. He is told that everyone has to wear expensive sweats. After selling a bunch of his dad's old junk to earn cash to buy the clothes, he turns up only to find that the actual dress code is "geek chic,". So everybody is actually dressed like Danny and his "loser" friends, not because Dash wanted to make fun of him, but because Dash didn't have the money to buy his own expensive sweats--having spent his last dollars on, ironically, Danny's garage sale. It's open to debate if Dash wanted to make fun of Danny or not. Dash's change of plans was emailed to the other invitees and he claimed to have forgotten Danny wasn't in the group of people who received the email.

* When ''WebVideo/TheNutters'' (mentioned above) was nominated for a Google Tech Festival award and the cast attended, Liam Gaynor was told that it was a formal event and arrived dressed in slacks, a shirt and nice shoes...only to find everyone else dressed casually.

* ‘’Series/NightCourt’’: A self inflicted version comes when Dan tries to sneak into the Distirct Attorneys Private Halloween party to social climb, dressing as Dorothy from ‘’Film/TheWizardOfOz’’ to do so. When he arrives, everyone is formally dressed and he sticks out like a sore thumb.

* A variant in ''Series/TheWildHouse'', where Natalie's invitation to a costume party gets destroyed and she has to piece it back together, resulting in her showing up wearing ''gold'' clothes rather than ''old'' clothes.

* Inverted in the ''Series/UnderTheUmbrellaTree'' episode "Holly Gets the Blues." Holly accidentally falls face-first into a tub of blue fabric dye just hours before she's supposed to go to a party, and though she manages to wash the dye off her face in time, she can't get it out of her hair. But then she learns that the party is a costume party, so she goes after all, dressed as a blue-haired clown.

* [[InvertedTrope Inverted]] in an episode of ''WesternAnimation/{{Doug}}''. Doug is invited to a party at BeBe's house and ends up with a large pimple on his nose right before. The entire episode plays on his attempts to get rid of it and his embarrassment. When he finally sums up the courage to go, Skeeter informs him that is actually ''is'' a costume party, allowing him to wear a mask to cover it up.

* The AlphaBitch character successfully pulled this on Amanda Bynes in ''Film/WhatAGirlWants''. In that case, the heroine was told to dress informally for a very formal event. It was subverted since she was initially mistaken for a model.

* Played with in Film/MeanGirls: (ironically given the plot of the film) it was more a genuine misunderstanding on the main character's part. She did not know that costume parties were just excuses for the popular girls to wear the skimpiest thing they can think of without being called anything derogatory, and she looks noticeably odd in a much more modest and traditionally scary Halloween costume.

* Subverted in an issue of ''Franchise/ArchieComics'', of all things. Veronica attempts to trick Betty by telling her that the most formal dance of the school year has been changed to a country-style hoedown and that she should dress accordingly. Betty believes her, but also passes the information on to her friends without mentioning the source, and since they regard Betty as trustworthy they decide it must be true. The news spreads to other students, the hired band, and the decorating committee, all of who change their plans and outfits accordingly -- so, on the night of the dance, it's the fancily dressed Veronica who ends up looking out place.