History Main / ImpostorExposingTest

* In ''Manga/Naruto'' an imposter outs himself by remembering the TrustPassword Sasuke set up, which Sasuke knew that Naruto wouldn't possibly be able to remember the entire thing, and the imposter had been spying on them.

The cast has been infiltrated by a [[ShapeShifting shapeshifter]], [[ReplicantSnatching replicant]], [[RidiculouslyHumanRobots robot]], or some other creature that is able to pass as human; or else someone formerly trustworthy has lost their humanity to TheVirus or some other [[PuppeteerParasite alien parasite]] and is now secretly working against them. How do the other characters determine which of them is no longer human?

[[caption-width-right:291:An impostor cat and famous cat are given food. The famous cat turns his nose, and the impostor downs the plate. Problem solved.]]

[[caption-width-right:291:A normal cat and famous cat are given food. The famous cat turns his nose, and the impostor downs the plate. Problem solved.]]

* ''Fanfic/AllAssortedAnimorphsAUs'': In "What if they saved Jake's family?", Eva makes everyone drink [[AlienCatnip instant maple and ginger oatmeal]]. If they can still form coherent sentences in an hour, they're not a Controller.

* A Brazilian Coca-Cola ad is set at a space station where the Captain informs the rest of the crew there's an alien disguised as one of them and, to expose it, he'll ask them a question he expects every Earthling to know the answer. A crew member brings up the fact they came from several countries as a reason to believe not everyone will know the answer but the Captain states than anyone from Earth will know. He asks what the world's best soda is and all Earthlings answer "Coca-Cola". The alien is exposed.

** Trying to distinguish the two Doctor Hs in the first movie, they pose to them the challenge of fixing a large, complex spaceship. (It was also a convenient way to get that spaceship fixed, since they didn't have the funds to do so otherwise.)

* In ''[[Recap/TheSmurfsBook4Story2TheFakeSmurf The Fake Smurf]]'', Gargamel uses a spell to transform imself into a Smurf to get revenge on them, but there's a small problem - no tail. So he improvises by making a fake one using a wooden fake tail, some blue paint, and glue. Unfortunately for him, when he's caught in his own attempt to sabotage their bridge, the fake tail falls off, a Smurf finds it, and brings it to Papa Smurf. When he realizes this must mean an impostor is around, he pinches the Smurf on the tail to make sure his is real, then the other Smurfs start doing the same to each other, and Gargamel's cover is quickly blown.

* In the LightNovel/TheFamiliarOfZero fanfiction,''Fanfic/TheSteepPathAhead'', the Vampires Amethyst and Daphne test the blood of whoever comes to claim to be Karin's daughter. They're giddy when they taste Louise's blood, confirming it's her. Likewise, her manticore familiar can smell whether or not they are the real deal.

* ''Film/TheThing1982'': Poking people's blood samples with a hot needle is used to identify the Thing, since the the Thing's blood will react to try to defend itself when endangered.
** In [[Film/TheThing2011 the prequel,]] they use a different test that can't tell who ''is'' a Thing, but can ascertain who ''isn't'': [[spoiler:it can't replicate inorganics. Like dental fillings, for instance. If you have cavities...]]

* ''Film/TheWorldsEnd'': To prove that they haven't been replaced by [[ReplicantSnatching "blanks",]] the characters decide to show each other the scars, tattoos, corrective surgeries or other modifications they got over the years. Gary refuses to do so [[spoiler:because they'd see he'd attempted suicide,]] but instead bashes his head several times against a support beam, showing he's not MadeOfPlasticine and doesn't bleed blue ink.

* ''{{Film/Ronin}}'': Sam tests some of the hired mercenaries in subtle ways. But the defining moment was when he exposed Spence, who claims to be part of the British SAS, as a fraud by calling him out not only on his tactics to take out the group's target, but asking him a question that shouldn't have flustered a real SAS soldier. [[spoiler: Notably, after the fraud has left, someone asks Sam the same question he was asking Spence; Sam shrugs it off with "How the f*** would I know?" Given that all SAS recruits are trained in resisting much harsher interrogation than repeated questioning, it doesn't matter that Sam didn't know the right answer to his own question, only that Spence couldn't keep his cool well enough to even attempt a bluff.]]
* ''[[Film/TheAssignment1997 The Assignment]]'' (1997). The plot involves Annibal Ramirez, who bears an [[IdenticalStranger uncanny resemblance]] to the terrorist Carlos the Jackal, being recruited by the CIA to impersonate Carlos. A terrorist who knows the real Carlos is surprised to see him at the duty-free counter at Heathrow Airport, because he left Carlos back in Libya.

* ''Literature/MagicTheGathering'': In the novel ''Planeswalker'', when Xantcha is accused of being a Phyrexian, she cuts herself to show that she bleeds blood rather than Phyrexian oil. However, she actually ''is'' Phyrexian: as a sleeper agent, she was created specifically to be able to pass this kind of test. Fortunately, given that as a first try she's actually very poorly equipped to pass for human, she's the first fully-organic Phyrexian the locals have encountered and this satisfies them. (Much later, she finds records implying her replacements' generation, despite improvements such as having a physical sex, were all exposed and killed.)

* ''Series/{{Alias}}'': "Project Helix" can make one person exactly like someone else, and there are three main ways to uncover the imposter. Of course, the imposters know all about this and spend lots of time on framing innocent people.

* Gaius Baltar spends most of the first season developing a Cylon detection test in ''Series/BattlestarGalactica2003''. Unfortunately, his [[ItsAllAboutMe self-serving]], [[DirtyCoward cowardly]], and at times down right stupid nature mean that even when test does expose someone he doesn't tell anyone the truth. After encountering a real Cylon that the rest of the fleet thinks passed the test, they assume the whole test was flawed. Interestingly, the first time he "invents" the test, he uses it to try to direct the people's attention to a device he doesn't recognize, so he picks a random guy he doesn't know and "reveals" him to be a Cylon. The guy is abandoned on a supply space station... and then he's revealed to really be a Cylon.
* ''Series/DoctorWho'': In [[Recap/DoctorWhoS29E1SmithAndJones "Smith and Jones"]], the Judoon have scanners which can distinguish humans from non-humans, which they try to use to find a plasmavore criminal hiding in a hospital. The plasmavore is able to change its physiology by drinking blood, and tries to use that to beat the test; however, the Doctor tricks it into feeding on him. Since he's a Time Lord, the scanners identify the plasmavore as non-human and kill it.

* In TabletopGame/IronKingdoms's game Warmachine, if more than one of the same character appears in a game then one of them is an impostor, with the one whose on the winning side being the real one.

* The Voight-Kampff test in ''VideoGame/BladeRunner''. It functions as an important tool for identifying replicants, as well as a unique and engaging game mechanic. The test automatically terminates after asking ten questions, regardless of whether a conclusive result has been obtained. The player can choose the nature of the questions, ranging from simple calibration questions (like those of a polygraph test), to enormously provocative questions involving child abuse and animal cruelty. In some cases, the questions the player chooses can be the difference between the test identifying the subject as a human or as a replicant.
* Spy checks in ''VideoGame/TeamFortress2''. Thanks to FriendlyFireproof, you can shoot your own teammates without hurting them, but if you shoot a Spy disguised as one of your teammates, they'll take damage. The Pyro's flamethrower is the classic choice, since only Spies will catch on fire. However, the spy has weapons in his arsenal which can enable short immunity to fire (like the Spy-Cicle knife) or fake a death (like the Dead Ringer watch).

* In ''VideoGame/Fallout4'', the player can encounter a small town called Covenant that has a test designed to root out Synths[[note]]In a MythologyGag, said test is the G.O.A.T. from ''VideoGame/Fallout3'' minus the question about the Overseer[[/note]]. The question that supposedly trips Synths up is "What position would you want to play on a baseball team?"; Synths will instinctively answer "Catcher" even if they don't know what catcher actually does. However, the test's efficacy is questionable at best, which is used to show how paranoid the people of Covenant are, since they're willing to treat a single multiple-choice question as damning evidence.

* On ''WesternAnimation/RegularShow'' a shapeshifting otter tries to take Rigby's place and the others can't tell them apart. To try to figure out which one's the real Rigby, they go through a series of tests, all of which they "pass" by failing miserably. It's finally when they ask what Rigby's secret fear is that the one that answers is declared the real Rigby and is given a hug by Mordecai... which outs him as the imposter, because the ''real'' Rigby would never hug Mordecai.
* In one episode of ''WesternAnimation/TheFlintstones'', Fred falls asleep at the company picnic, and dreams he pulls a RipVanWinkle, sleeping for decades. Unable to find Wilma when he wakes up, he eventually finds Barney, who's now a millionaire. Barney isn't sure it's actually Fred, however, seeing as he's been missing for years and fakes keep showing up trying to get their hands on Barney's money, but he knows how to make sure: he calls for Dino. When Dino sees his old master and responds the same way he always did (which is happily leaping and tackling Fred, then licking his face) Barney knows it's really Fred.

* In his account of the making of a Navy SEAL, ''Damn Few'', Rorke Denver recounts the night his SEAL unit went for a beer to find a guy sitting at the bar who was claiming to be a SEAL. His dress, attitude, demeanor and presentation were subtly wrong and a long-suffering waitress tipped them off that "Billy" used his Seal status to scare people. The least threatening real Seal was sent to quiz the suspicious Billy about where he'd been, who he'd trained with and what his combat specialties were. He failed on every test. When Billy went to the men's room, the largest and hardest SEAL followed him in. A little discussion ensued and Billy ended up running for his life, stripped of his fake badges--which later ended up pinned to the real Seals' mess-room wall with a combat knife.

* ''WesternAnimation/PunkyBrewster'': In the episode "Double Your Punky", Glomer creates a clone of Punky from a photograph to keep him company at home while she's at a school picnic. This Punky clone is obnoxious, however, and in his confusion to corral her, he zaps the sweet Punky back into the photograph. When the two Punkys face each other, nobody can tell who is who--nobody except her dog Brandon, who recognizes her scent, jumps on her and licks her face profusely.

* ''{{Film/Ronin}}'': Sam tests some of the hired mercenaries in subtle ways. But the defining moment was when he exposed Spence, who claims to be part of the British SAS, as a fraud by calling him out not only on his tactics to take out the group's target, but asking him a question that shouldn't have flustered a real SAS soldier.

--> '''Nash:''' Look! I am not this Ernest guy. I just happen to look like him. I switched with him, get it? Would the real Ernest be able to knock out Chuck? Or set a time bomb without it going off in his face? And look at the floors. Notice how clean they've been lately?

* Near the end of ''Manga/{{Parasyte}}'', the military figures out that people who've been taken over by the parasites can be identified by looking at x-rays of them -- the parasites don't have skulls. They root out the parasites hiding among the people at City Hall by leading them past a large x-ray machine.
* Subverted during ''Manga/YuYuHakusho''. Patches were placed on the protagonists that were originally designed to indicate if the characters were harmed, but doubled as a way to indicate an imposter as only the person who placed them on another could remove them. [[spoiler: It didn't work and they resort to SpotTheImposter tactics instead.]]
* PlayedForLaughs in an episode of ''Anime/{{Pokemon}}''. Two ditto have snuck into the group's camp by impersonating their Pokemon. In an attempt to weed out the impostors, they return some of their Pokemon to their pokeballs, but when one of the ditto impersonates Piplup, Ash's Gible uses Draco Meteor, which has a tendency to home in on Piplup.

** Trying to distinguish the two Doctor H.s in the first movie, they pose to them the challenge of fixing a large, complex spaceship. (It was also a convenient way to get that spaceship fixed, since they didn't have the funds to do so otherwise.)
* In ''Animation/PleasantGoatAndBigBigWolf: Mighty Little Defenders'' episode 27, Weslie finds the other goats trapped in cages but with several of Wolfram's mud golems in each cage posing as each goat. Weslie's initial methods of trying to pinpoint the real ones fail since the golems thought a couple of steps ahead (the golems are ordinarily weak to water, but the goats' doppelgangers applied waterproof lotion to themselves; they also closely studied the actual goats' lives and personalities and can answer Weslie's questions about them easily). In the end, Weslie [[spoiler:gets the gang's weapons back from a couple of other golems and uses them to determine who is who, since the weapons can only be used by their respective owners]].

* In ''[[Recap/TheSmurfsBook4Story2TheFakeSmurf The Fake Smurf]]'', Gargamel uses a spell to transform imself into a smurf to get revenge on them, but there's a small problem - no tail. So he improvises by making a fake one using a wooden fake tail, some blue paint, and glue. Unfortunately for him, when he's caught in his own attempt to sabotage their bridge, the fake tail falls off, a Smurf finds it, and brings it to Papa Smurf. When he realizes this must mean an imposter is around, he pinches the Smurf on the tail to make sure his is real; then the other Smurfs start doing the same to each other, and Gargamel's cover is quickly blown.

* In the LightNovel/TheFamiliarOfZero fanfiction,''Fanfic/TheSteepPathAhead'', the Vampires Amethyst and Daphne test the blood of whoever comes to claim to be Karin's daughter. They're giddy when they taste Louise's blood, confirming its her. Likewise, her manticore familiar can smell whether or not they are the real deal.
* Discussed in ''[[https://www.fanfiction.net/s/13496321/1/Star-Wars-Legends-Never-Die Star Wars: Legends Never Die]]'' when Luke Skywalker and Mara Jade of ''Franchise/StarWarsLegends'' find themselves in the events of ''Film/TheForceAwakens'' and Luke has to convince Han that he's real. While certain details of Luke and Han's pasts are different between universes, Han appreciates that this Luke mentioning a past wedding where 'his' Han left a woman at the altar because he wasn't ready is too specific a detail about someone he's never met to be completely random, and Luke still has a similar fighting style to his other self.

** In [[Film/TheThing2011 the prequel]], they use a different test that can't tell who ''is'' a Thing, but can ascertain who ''isn't'': [[spoiler:it can't replicate inorganics. Like dental fillings, for instance. If you have cavities...]]

* In the ''Film/TheTerminator'', one reason Kyle Reese literally [[PetTheDog pets the dog]] is because dogs can detect Terminators (by furiously barking their heads off); in the robot-dominated future, resistance members have at least one dog hanging around the entrance of their bases to administer this test on all who enter.

* ''Film/TheWorldsEnd'': To prove that they haven't been replaced by "[[ReplicantSnatching blanks]]", the characters decide to show each other the scars, tattoos, corrective surgeries or other modifications they got over the years. Gary refuses to do so [[spoiler:because they'd see he's attempted suicide]], but instead bashes his head several times against a support beam, showing he's not MadeOfPlasticine and doesn't bleed blue ink.
* At the final scene of ''[[Film/PoliceAcademy Police Academy 6: City Under Siege]]'', the heroes are in the same room with Commissioner Hurst and the BigBad, who is disguised as Hurst. Their test to reveal the imposter is called "the Pinocchio-test", and is rather simple. (They perform a nose pull on both commissioners, revealing the imposter to be wearing a rubber mask).
* ''{{Film/Ronin}}'': Sam tests some of the hired mercenaries in subtle ways. But the defining moment was when he exposes Spence, who claims to be part of the British SAS, as a fraud by calling him out not only on his tactics to take out the group's target, but asking him a question that shouldn't have flustered a real SAS soldier.

* PlayedForLaughs in ''Film/ErnestGoesToJail'' with EvilTwin Felix Nash. He makes zero attempt to look, act, or sound like Ernest aside from his physical looks and wearing most of Ernest's iconic outfit, acts blatantly OutOfCharacter around them and does things they know Ernest would never do, and gets caught red-handed robbing the bank and they still fail to realize it. He gets so fed up with it that ''he outright tells them he's going to rob the bank and they still fail to realize he's not Ernest''. It's not until he applies an imposter exposing test to himself, after having tied up the bank employees, by pointing out how well and competently he's been doing things that they finally realize he's not Ernest.

--> '''Charlotte:''' You ''ARE'' an imposter!

* In the ''Literature/{{Deryni}}'' novels, there's a [[FantasticDrug drug]] called ''merasha'' that causes an immediate and violent reaction in Deryni but has no significant effect on "normal" people; during the persecutions, it was used as a way of uncovering secret Deryni. One application is specifically mentioned in the short story "The Priesting of Arilan": whenever a new priest was ordained, the communion wine at the Ordination Mass was spiked with the drug to make sure no Deryni got into the Church.

* ''Literature/TheDresdenFiles'': Murphy has Mort cut himself in ''Literature/GhostStory'' before inviting him inside. A lot of supernatural beings that [[MustBeInvited require an invitation to enter a building]] will bleed ectoplasmic goo rather than blood. The invitation, or lack thereof, is another such test in and of itself — an imposter using magic will either not be able to enter, or not maintain their disguise. Murphy pulls this one on Dresden himself, after, in a previous book, being attacked by someone taking his form.

* ''Literature/MagicTheGathering'': In the novel ''Planeswalker'', when Xantcha is accused of being a Phyrexian, she cuts herself to show that she bleeds blood rather than Phyrexian oil. However, she actually ''is'' Phyrexian: as a sleeper agent, she was created specifically to be able to pass this kind of test. Fortunately, given that as a first try she's actually very poorly equipped to pass for human, she's the first fully-organic Phyrexian the locals have encountered and this satisfies them. (Much later she finds records implying her replacements' generation, despite improvements such as having a physical sex, were all exposed and killed.)
* Partially subverted in the German SF novel ''Der Mann von Oros'', where a blood test is used to dramatically reveal the shapeshifting alien whose frozen 'corpse' was taken aboard the vessel rescuing the surviving members of the stranded Pluto expedition...but ''fails'' to similarly detect a second alien [[spoiler: who had already replaced one of the castaways on Pluto weeks before and thus had more time to perfect his disguise]]. This second alien is the 'man from Oros' alluded to in the title [[spoiler: and the story's protagonist]].
* Played with in Asimov's short story ''No Refuge Could Save''. A spy is tripped up by being familiar with the third verse to "The Star Spangled Banner", something no true American would know.

-->'''Wolverine:''' Hey, hey! It's me.
-->'''Cyclops:''' Prove it.
-->'''Wolverine:''' You're a dick.
-->'''Cyclops:''' Okay.