When characters are mistaken for the beings of another world. If you [[TimeTravel travel through time]] (especially to the mid-20th century or thereabouts) or are an astronaut, this will probably happen to you at least once.

Yet another variant of MistakenForIndex. For aliens not from space, see MistakenNationality.
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!!Examples

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[[folder: Anime ]]

* [[TheCutie Rena]] from ''HigurashiNoNakuKoroNi'' mistook her friends for aliens in "The Atonement" chapter. [[spoiler: Of course, she was at best, at lv.4 [[HatePlague Hinamizawa Syndrome]].]]
* One episode of ''OuranHighSchoolHostClub'' had Honey's younger brother Yasuchika accuse him of being an alien simply because he eats three cakes at once ''in less than a second'' once a week.
* ''FrankenFran'' helps an actress who has fallen for a male lead who is obsessed with anime features, and wants to star opposite him in live-action adaptations. She insists on ever more extensive surgery but fails to take Fran's advice at the hazards in her rush to bed the actor, and cosmetically falls to pieces. He flees in terror, then goes on so many talk shows raving about Grays trying to abduct him that he doesn't get any more roles.
* A running gag in ''ShinryakuIkaMusume'' - [[HotScientist Cindy Campbell]] and her [[StupidScientist colleagues]] are convinced that [[CuteMonsterGirl Ika Musume]] is from outer space, and they would very much like her to [[TheyWouldCutYouUp visit their laboratory]].

[[/folder]]

[[folder: Comic Books ]]

* The Comicbook/{{Teenage Mutant Ninja Turtles|Mirage}} do this on purpose in the third Mirage comics volume; aliens having openly made contact with Earth, it's apparently easier for people to accept that than homemade mutant freaks.

[[/folder]]

[[folder: Film ]]

* In ''Film/BackToTheFuture'', the [=DeLorean=] TimeMachine was mistaken for a UFO in 1955 due to its gull-wing doors. The fact that Marty was wearing a radiation suit at the time didn't help.
** He turns it to his advantage later, when he orders his father [[AliensMadeThemDoIt to hook up with his mother]].
* Grand Fenwick's chainmail-clad longbowmen successfully invade 1950s New York City in ''Literature/TheMouseThatRoared'' because of being mistaken for Martians.
* PlayedForLaughs in ''Film/TheAvengers'' where Bruce Banner as the Hulk falls on a warehouse, half-destroys it and becomes human again. There, he speaks to an old man, a security guard, who believes Bruce is some sort of alien. The security guard is played by Harry Dean Stanton, who was in Film/{{Alien}}.
* In the ''Film/SuperMarioBros'' movie, when Mario and Luigi are escaping from the police force, a news report identifies them as "alien plumbers".
-->'''Luigi''': Aliens? We've gotta deal with aliens too?
-->'''Mario''': Luigi, ''we're'' the aliens!
-->'''Luigi''': We are? ''Cool!''
* [[http://www.youtube.com/watch?v=YnJatP5Ebu8 This scene]] from ''Film/{{Eraser}}''.

[[/folder]]

[[folder: Literature ]]

* In SpiderRobinson's ''The Free Lunch'', when the protagonists notice that there's something very odd about some of the attendees at the theme park where they live, their initial deduction is aliens. [[AuthorAppeal This being Spider Robinson]], however, they're actually time travellers.
* ''Take Me to Your President'' by Leonard Wibberley was about a fellow nicknamed "A-1" from a small British town called Mars, who accidentally got loaded into an experimental rocket. When it landed somewhere other than it was expected to, and he came out wearing the space suit he'd found and saying he was from Mars, well....
* In Amy Thomson's ''The Color Of Distance'' has the protagonist, Dr. Juna Saari, spend five years among the alien Tendu, who give her a moist color-changing skin and internal linings that keep her hair from growing and let her breathe particulates and eat foods which she'd normally be lethally allergic to. When humanity comes back to pick her up, the first contact is with a suited man who thinks she's one of the Tendu, and she plays along for a bit before saying "I believe the line is 'Dr. Livingston, I presume?'"
* Christine Peacock sees mysterious lights in a field near the vicarage in ''[[AuntDimity Aunt Dimity Digs In]]'', and she's convinced she saw aliens land there. She's even more convinced when a circle of trampled-down grass is found on the spot the next morning. In fact, [[spoiler: Sally Pyne and one of the archaeology students were exercising there at night, mostly because Sally was embarrassed to be seen exercising]].
* A long-running plot point of ''{{Literature/Animorphs}}''. The Yeerks thought the kids were Andalites.

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[[folder: Live Action TV ]]

* "Tomorrow is Yesterday" from ''Series/StarTrekTheOriginalSeries''.
* The ''Series/IDreamOfJeannie'' episode [[http://www.tv.com/i-dream-of-jeannie/u-f-oh-jeannie/episode/252763/summary.html?tag=reviews;episode;2 "U-F-Oh Jeannie"]], where Tony was mistaken for a Martian by a group of rednecks in the DeepSouth.
* In ''KyleXY'', Josh Trager claims, half-jokingly, that Kyle is an alien. (In fact he's an experimental clone with psychic powers.) Two years later, when Kyle finally reveals his history to the Tragers, he comments that Josh's guess may have been the closest to the truth.
* In the ''Series/LostInSpace'' episode "Visit to a Hostile Planet", the Robinsons go back through time to 1947 and are mistaken for aliens when they land on Earth.
* In ''Series/TheAddamsFamily'', the Addams are mistaken for aliens by the military, who approach them claiming to wish peace and asking them lots of questions. As a consequence, The Addams believe the army men are aliens as well (because of their green wardrobe).
* [[Series/StargateSG1 SG-1]] deliberately invokes this when they're stranded in 1969, presumably figuring that it's a quicker explanation than the actual one.
** Quicker, maybe, but the main reason was to avoid paradox. (Although that didn't stop Jack from going by the names of fictional characters, some of whom already existed and others didn't, but [[RuleOfFunny who cares]]? They didn't want to [[ButterflyOfDoom endanger the Stargate program by accident]].
* Averted in the TV Show, ''Series/{{Community}}''. Abed plans to 'mess with' Troy by using the classic sitcom set up for this, except that he didn't fool Troy for a second.
* Done in the ''Series/{{Torchwood}}'' episode "Countrycide", where the team thinks that some aliens are responsible for disappearances and attacks. Turns out, it's a bunch of [[IAmAHumanitarian humanitarians]].

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[[folder: Web Comics ]]

* Played straight and then subverted in [[http://bobadventures.comicgenesis.com/d/20070717.html this]] strip from ''Webcomic/TheInexplicableAdventuresOfBob.''

[[/folder]]

[[folder: Western Animation ]]

* During the episode "Mush-Rumors" of ''WesternAnimation/TheAdventuresOfSuperMarioBros3'', a human family ends up driving into the Mushroom Kingdom by accident and are called aliens by one of the Toads, which then gets spread and exaggerated to the point where Bowser thinks they're an alien invasion force in disguise. The fact that they look not-unlike the human Mario and Luigi never comes up.
* There's a ''[[WesternAnimation/TheSimpsons Simpsons]]'' episode (''Series/TheXFiles'' crossover) where Mr. Burns is mistaken for an alien from the results of the various dubious medical treatments he undergoes and glowing green in the dark, a side effect of working at the nuclear power plant.
* ''WesternAnimation/SpongebobSquarepants'' had an episode with them using Sandy's rocket to land "on the moon" (actually they circle around the moon and land back in Bikini Bottom) and go to hunt "moon clone aliens" which look exactly like their friends on earth.
* An episode of ''WesternAnimation/TheMask'' animated series featured a government agent and a scientist mistaking The Mask for a hostile alien due to a series of coincidences (not that it's hard to mistake him as such in the first place...)
-->'''Agent''': Hmm...Subject has green skin. Imagine! Just like in the funny papers!
* Inverted and played straight in one episode of ''WesternAnimation/VivaPinata''. Fergie Fudgehog is conned onto going onto a defective rocket ship that crashes. When he comes out, his foggy helmet makes his friends look like aliens to him, and it makes him look like an alien to his friends! Needless to say, {{Hilarity Ensues}}.
* The ''WesternAnimation/HeyArnold'' Halloween episode. Also doubles as a ParodyEpisode due to all the ''Creator/OrsonWelles'' references.
* In ''The Santa Claus Brothers'', one of the elves is mistaken for an alien.
* In the ''WesternAnimation/SouthPark'' episode "Starvin' Marvin in Space", the people of Australia thought Marvin was an alien. To be fair, he ''did'' emerge from a spaceship.
* An episode of WesternAnimation/{{Gargoyles}} has an actual alien think the title characters are also aliens.
* ''WesternAnimation/InvaderZim'' has an unfinished episode where Zim tricks Dib into thinking Poonchy, Drinker of Hate was an Irken invader. HilarityEnsues.
* A series of unlikely coincidences cause [[WesternAnimation/PhineasAndFerb Candace]] to believe that Ferb is an alien. She's obviously wrong, but Phineas and Ferb ''are'' helping an alien rebuild his spaceship.
* ''WesternAnimation/RockosModernLife'', where he and Heffer think Filbert is an alien after reading his diary. It was AllJustADream, but they were still freaked out.
* ''WesternAnimation/{{Rugrats}}'' did this several times.

[[/folder]]

[[folder: Real Life ]]

* After YuriGagarin became the first human to enter space and return successfully, a woman who saw his capsule land asked him "Can it be that you have come from outer space?" He replied [[http://en.wikiquote.org/wiki/Yuri_Gagarin "As a matter of fact, I have!"]]
** Most likely apocryphal, since it's now known that he actually bailed out of his capsule, and wouldn't have landed near it.
* Similarly, when John Glenn was orbiting in the Friendship 7 in 1962, the mission planners weren't exactly sure where the capsule would land - somewhere near Australia, as in any part of Australia or the surrounding oceans or islands for a pretty far distance. Glenn was worried what the aboriginal Australians might think when seeing a man in silver emerge from something that fell from the sky so he took a short speech with him rendered phonetically: "I am a stranger. I come in peace. Take me to your leader, and there will be a massive reward for you in eternity."
* Allegedly happened to an SAS troop doing a training exercise involving a High Altitude Low Opening parachute jump. Having landed in the middle of nowhere in the middle of the night, they walked up to the nearest farmhouse to get directions. A woman opened the door and found herself facing several tall beings dressed head-to-toe in black including oxygen masks and blinking formation lights.
-->'''Troop leader:''' "Excuse me, ma'am. Can you tell us where we are?"
-->'''Woman:''' "Earth!" ''(slams door in their faces)''
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