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[[quoteright:259:[[ComicBook/ArchieComicsSonicTheHedgehog http://static.tvtropes.org/pmwiki/pub/images/sonic_8.jpg]]]]

->'''Negative Lizzy:''' So, how did you figure out I wasn't really your stupid girlfriend?\\
'''Numbuh One:''' When I look into Lizzie's eyes, I can tell she's not a ''jerk''.
-->-- ''WesternAnimation/CodenameKidsNextDoor'', "Operation: P.O.O.L."

The [[InvertedTrope inversion]] of SomethingOnlyTheyWouldSay: When a character is pretending to be someone else, they may unwittingly reveal this by saying something that would be out-of-character for who they're impersonating. Variations include not responding to a well-known BerserkButton, doing things they're normally afraid of (or have a similar excuse for never doing), [[InsistentTerminology expressing hatred for a nickname they insist to be called by]], or otherwise {{invok|edTrope}}ing OOCIsSeriousBusiness. A common variation in Japanese media is [[UsefulNotes/JapanesePronouns using the wrong pronoun.]]

Often {{Invoked|Trope}} in kidnapping and IHaveYourWife scenarios, to let [[TheHero the heroes]] know that something is amiss. If the BigBad is demanding a ransom, this is to alert them to the fact that it's a trap; if he wants the kidnapped to "assure" TheHero that the kidnapped is "in fact" okay, this is to secretly convey that they're not. Sometimes serves as a QuietCryForHelp. If they've pre-arranged such an alert, this is a CovertDistressCode.

Real-life military personnel sometimes use hand signals when being taped to communicate in another way with their 'home base'. There are a few documented cases of [[CovertDistressCode soldiers giving hand signals (and one case of them just flipping the bird to the camera) to alert the people receiving it that no, they weren't being treated very politely at all]]. And some have done it just for fun, giving the [[http://www.snopes.com/photos/military/crossed.asp sign for coercion when forced to shake a politician's hand,]] for instance.

Compare with LyingFingerCross (a common gesture used in this trope), NotHimself, OohMeAccentsSlipping, and TrustPassword (a pre-arranged alert to confirm one's identity and freedom of action). Contrast with SomethingOnlyTheyWouldSay (in which a character is identified by a characteristic) and BluffTheImpostor. Sister Trope to YouCalledMeXItMustBeSerious and BatmanGrabsAGun. See also OOCIsSeriousBusiness.


* In an early '70s TV commercial for the short-lived Cap'n Crunch variant Vanilly Crunch, the good captain's ship is approached by Wilma the Whale, the mascot for that cereal. After the captain does a description of the cereal, he shoots a cannon at the whale! Turns out that pirate Jean [=LaFoote=] (the "bad guy" in these ads) had disguised his now-sinking vessel as Wilma. Cap'n Crunch knew it because he described Vanilly Crunch and the whale didn't smile.

[[folder:Anime and Manga]]
* ''Manga/FullmetalAlchemist'':
** Riza Hawkeye takes advantage of this trope to trick Envy, who is disguised as Roy Mustang, as part of her BatmanGambit. She aims a gun at him, saying that Roy never calls her "Lieutenant" in private. Cue Envy immediately breaking the form, cursing his luck and shouting "[[EveryoneCanSeeIt I]] ''[[EveryoneCanSeeIt knew]]'' [[EveryoneCanSeeIt there was something going on with you two]]!" Her reply can effectively be summed up as, "Not really. [[YouJustToldMe Thanks for believing me, Envy]]." Cue epic beatdown.
** Earlier in the series, Roy Mustang uses a similar trick to subtly pass some information to Edward Elric and Major Armstrong. He recommends that the Major take a trip to the east to soothe his frazzled nerves, as the women there are very beautiful. While Mustang frequently makes womanizing comments (part of his carefully crafted persona), this particular remark comes across very oddly because to the east of their country is nothing but a ''desert'', and it seems strange that he would recommend it as a destination. [[spoiler:They check it out anyway. It turns out to be where Mustang has smuggled a (rather cute-looking) female officer under Armstrong's command, Maria Ross; she was falsely convicted of murder, and most of the country believes ''he'' murdered her since the dead person was his best friend.]]
* This trope is a key plot point in the ''Anime/WeissKreuz'' OAV ''Verbrechen ~ Strafe''. During a mission briefing, when asked if she's well, Weiss's [[TheHandler handler]] Manx replies that she's having trouble with her allergy to black lilies. Much later, when Weiss finish springing their trap on the villain who was holding Manx hostage, they reveal that "[[FlowerMotifs black lily]]" is a codeword indicating "lies," and that Manx's comment had alerted them to the fact that the orders given in that mission briefing were fraudulent.
* ''Manga/{{Naruto}}'':
** In the Chuunin exams arc, Sasuke proposes using a TrustPassword in case of enemy ninjas using doppelgangers to imitate one of them (again), and makes up a long poem as the passphrase. A few scenes later, Naruto excuses himself to pee, and when he returns he is quizzed for the passphrase, and successfully gives it. Of course, Sasuke knows that the real Naruto would not have remembered such a long passphrase, and that he was being spied on when he made it.
** Also during the Sasuke Retrieval arc. After defeating Jirobou of the [[QuirkyMinibossSquad Sound Four]], Shikamaru disguises as him and catches up with the other three. When he does, Tayuya cusses him out and asks what took him so long. Shikamaru, still disguised, quietly apologizes. The other three immediately realize he's not Jirobou, as Jirobou always chastised Tayuya for using unladylike language.
** Used again much later by the Mizukage to [[spoiler:tell that when they found Ao he was being controlled by someone else's technique by the fact that he agreed when she said she would remove the seal around his Byakugan (when none of them could) and apologized to Chojuro (who he had previously been DrillSergeantNasty towards)]].
** When [[spoiler:Zetsu clones]] are infiltrating the allied forces in disguise, Sakura realizes Neji is one when he refers to Tonton as if she were a person, rather than Tsunade's pet pig.
* A peculiar example from ''Anime/{{K}}'' -- the Silver King Adolf K. Weismann has lived alone in an airship for decades with no contact with anyone. How, then, does the Blue King Reisi Munakata realize that something has been strange with him and that this should be investigated? Well, for the entire time he's been around, Weismann has flown his airship in "curiously repetitive" flight patterns that always correspond to the optimal path, based on the weather. Since the night of the murder the characters have been investigating, though, the airship has been moving in erratic patterns, completely unlike anything before. Sure enough, it ''is'' connected...
* Towards the end of ''LightNovel/GonnaBeTheTwinTail'', Souji ends up trapped in a LotusEaterWorld in which his various female comrades are throwing themselves at him. It's not until Twoearle starts to tie her hair in twintails that Souji realises something is wrong: the real Twoearle had vowed never to do that again. The fake world swiftly unravels.
* This happens in ''Manga/FushigiYuugi'' when the mirror-Miaka tries to seduce Hotohori to overpower both him and Tamahome, while keeping the real Miaka trapped inside a MagicMirror. Before she can kiss him, though, Hotohori lifts his sword to stop her. When the mirror-Miaka asks what's going on, Hotohori tells her that [[AllLovingHero Miaka]] would never behave that way.
* A variant was used in ''Anime/SCryed'': Kazuma, trapped in Unkei's LotusEaterMachine Alter, is challenged by that world's Ryuho to a friendly sparring match. They draw, and Ryuho offers him a hand up. This so badly clashes with Kazuma's memory of him that the illusion cracks, and he pulls out his Alter. The illusory Ryuho panics and begs for his life... at which point Kazuma destroys the illusion -- the Ryuho ''he'' knows would just summon his Alter and counterattack.
* In ''Manga/TsubasaReservoirChronicle'', Princess Sakura is seemingly trapped in a bubble and Syaoran is warned that if he fights back, she'll get hurt. He takes the blows, but when 'Sakura' calls out "Syaoran!", he knows she's a fake because she lost her memory, so she is now polite with him and says his name with the -kun honorific.
* In the Devil's Trill arc of ''Manga/DescendantsOfDarkness'', Hisoka figures out that Tsuzuki is possessed by Sargatanas very simply: first, Tsuzuki doesn't take up an offer to go out to eat, something he would never do. Second, Hisoka mentions that he bought their boss salted cuttlefish since he hates sweets, which doesn't get commented on by Tsuzuki. In fact, the boss is infamous for his SweetTooth.
* In ''Manga/{{Eyeshield 21}}'', at the start of the second half of the Devil Bats' game with the Shinryuji Nagas, Hiruma says their chances of winning are almost 0%, and that the team shouldn't do anything drastic as to harm their future careers. [[spoiler: Turns out it was all an act; everybody knows Hiruma would never tell them to give up unless the odds were exactly zero, so everyone (and we do mean ''everyone'') silently went for an onside kick as to not let the enemy know they were changing plans.]]
* ''Manga/OnePiece'':
** Vivi begins to suspect that there's something wrong with Usopp when he tells her to abandon the injured Carue, referring to him as "that bird." The real Usopp not only knows Carue's name, but is fairly close to Carue. In fact, it was Mr. 2 (Bon Clay) impersonating him in order to trick her.
** Another example occurs post-TimeSkip with the Impostor Straw Hat Pirates, who try to take advantage of the real Straw Hats' infamy to recruit powerful pirates for their journey into the New World; the leader, Demalo Black/Fake Luffy, does so by using Luffy's reputation (especially his rather colorful heritage) to do what he wants. His doing so ends up being one of the main reasons the Marines are able to tell that they're not the Straw Hats, since the real Luffy would ''never'' take advantage of his reputation to bully civilians.
* In the ''Anime/MaiHime'' manga, Haruka begins to suspect that she is in a LotusEaterMachine when her rival Shizuru humbly says that she should never have competed with her. Haruka points out that she finds Shizuru to be quite arrogant, and that [[ButtMonkey she could never be this happy]].
* ''Anime/DragonBallZ'':
** After Cell absorbs Android 17, he tries to persuade 18 to "join" him by [[VoiceChangeling using 17's voice]]. As he talks about how amazing the power feels, 18 looks uncertain... but when Cell refers to their creator, [[MadScientist Dr. Gero]], a little too glowingly, 18 sees through it and snaps that she and 17 actually hated Gero for turning them into cyborgs, and 17 would ''never'' care about his plans.
** At one point in ''Anime/DragonBallGT'', Goku knew immediately that a mind-controlled Vegeta is NotHimself because he was calling him "Goku". The real Vegeta always made a point of referring to Goku by his ''Saiyan'' name, Kakarot.
** In ''Anime/DragonBallSuper'': During the Tournament of Power, it appears as though [[spoiler:Frieza has turned on Universe 7 when he helps Frost attack Gohan. However, Gohan, who has fought Frieza in life-and-death battles in the past, immediately realizes that Frieza isn't being serious in his attacks, which is very strange given Frieza's level of hatred for the heroes; if he really was fighting to kill, he'd be going all out. It turns out to be a charade to get Frost to lower his guard, as he believes Frieza has turned to his side... only for Frieza to immediately knock Frost off the ring without even a fight, and then leave Gohan alone.]]
* ''Franchise/SailorMoon'':
** In ''Sailor Moon R'' one of the MonstersOfTheWeek disguise themselves as Chibi-Usa's dear mom [[spoiler: (Neo-Queen Serenity aka Usagi's future self)]] and calls to her using the name "Rabbit". Chibi-Usa is at first fooled, happy to see her mom again, and runs to hug her... but then she suddenly stops and asks the monster "Who are you?!" When the monster replies that she's her mother, Chibi-Usa says she's lying because her mother never calls her "Rabbit", ''which is what'' '''the Black Moon Clan''' ''refers to her as''. (Chibi-Usa's actual mother uses "Small Lady" instead.) In the dub, this is reversed: "Small Lady" is what the Dark Moon calls her, and how she finds out her mother is a fake.
** In the ''Sailor Moon [=SuperS=] Movie'', Sailor Moon gets trapped in a dream world while trying to rescue an abducted Chibi-Usa. There she meets Mamoru, but suspects something wrong when Mamoru suggests she abandon her mission and her team to stay with him. Her suspicions are confirmed when she baits him by asking who he likes better: Her or Chibi-Usa -- and he easily picks Usagi. This is a CallBack to earlier in the movie when real Mamoru could not answer this question since he was being asked to choose between his future wife and daughter, both of whom he loves dearly and deeply.
* In ''VideoGame/TheKingOfFighters'' manhua by Andy Seto, [[TheVamp Vice]] [[HoneyTrap attempts to seduce]] [[BrainWashing and then brainwash]] [[TheHero Kyo Kusanagi]] [[MasterOfDisguise while disguised as his girlfriend Yuki]]. Kyo blows her cover when she's about to kiss him and he stops her; he then says that, due to the context they're in, [[{{Tsundere}} Yuki]] would actually be ''upset'' at him, not throwing herself at him for a kiss.
* In ''Manga/CardCaptorSakura'', Sakura was confused and hurt because the ghost of her mother Nadeshiko led her to a DeathTrap (trying to drown her in the manga, getting her to walk off a cliff in the anime); she asks Yukito about it and he says that a mom would never want her child to be in danger. Later, when the "ghost" tries it again, Sakura remembers this and confronts it, saying "You're not my mom! TELL ME, WHO ARE YOU?!". It turns out it was a Clow Card, more exactly [[MasterOfIllusion The Illusion]], trying to avert being captured. [[spoiler: The ''real'' Nadeshiko's ghost had actually [[MamaBear SAVED Sakura from death]] via either pulling her out of the pool (manga) or slowing her fall enough for Yukito to catch her (anime).]]
* In ''Anime/FreshPrettyCure'', Love Momozono's mom gets captured and duplicated by a monster. Setsuna, who by that point had been HappilyAdopted into the Momozono family, figures it out first, but Love is fooled and gets in a fight with Setsuna because she thought Setsuna was being ungrateful to their mother. Later, Love figures it out because the monster-mother keeps mentioning Chiffon -- who Love had ''never'' mentioned by name to her parents before. She then tests the fake by putting on a red bracelet that the real Mrs. Momozono had made for Setsuna; the monster-mother tells Love that it looks good on her, which confirms Love that the monster is a fake and alows her to properly confront her -- her real mother would know that the red bracelet was made for Setsuna ''and'' there was a pink one for Love.
* ''Manga/{{Saiyuki}}'': When Chin Yisou creates a fake Goku, the team catches on almost immediately, and Sanzo promptly shoots it in the head. When Chin Yisou asks what gave it away, Gojyo explains that [[BigEater Goku]] would have asked for food the moment he showed up (though Sanzo's dialogue suggests he may have sensed something on a more instinctual level). The scene immediately cuts to the real Goku complaining that he's hungry.
* ''Manga/KOn'': This is one of the things that blows Ui's cover when [[TwinSwitch she's pretending to be her older sister Yui]] while the Light Music Club are practicing for the second school festival when the latter is sick. The whole club is fooled because of how close they look visually and Ui is really good at picking up things like her sister, so at first they practice without anyone the wiser. But then the band members notice "Yui" keeps time too well. In the ensuing discussion, she calls Azusa, Ritsu, and Tsumugi the wrong [[UsefulNotes/JapaneseHonorifics honorifics]] ("Azusa-chan", "Ritsu-san", and "Tsumugi-san"; Yui uses "Azu-nyan", "Ricchan", and "Mugi-chan"), and when challenged Ui could not produce Yui's nickname for Azusa. Astute viewers can also catch "Yui" wearing the wrong color UsefulNotes/InsideShoes when she first walks into the scene, something which all the members miss. Likely the others were so relieved at seeing "Yui" after missing several days they weren't paying attention.
* In ''Manga/NatsumesBookOfFriends'', everyone does notice [[spoiler:Natsume]] is acting strange when [[spoiler:Nyank-sensei impersonates him]] but assumes he just wasn't feeling well. However, [[SecretKeeper knowing his involvement with]] [[{{Youkai}} youkai]], Tanuma does figure out it's not him and gets [[spoiler:Sensei]] to reveal himself, [[spoiler:much to Natsume's dismay]].
* Happens in ''Manga/GunsmithCats'' when Becky is being held at gunpoint to lure Rally into an ambush over the phone. Rally realizes there's a serious problem when she notices she didn't send Becky her fee and Becky made no comment whatsoever.

[[folder:Audio Play]]
* In the first episode of ''AudioPlay/TheElysiumProject'', Ian figures out that the Jessica that he's talking to is actually [[MasterOfDisguise Mirage]] when "she" accidentally gives away that she doesn't know about the rendezvous point that they had set up with the other escaped subjects.

[[folder:Comic Books]]
* In a ''ComicBook/SpiderMan'' comic, Eddie "ComicBook/{{Venom}}" Brock's ex-wife (who is surrounded by police) addresses him as Edward over the phone. Displaying his typical lack of subtlety, Eddie immediately shouts "WHO'S WITH YOU?!"
* In one episode of ''ComicStrip/FlashGordon'', Dale distinguishes the real Flash from an impostor when the fake announces that he loves her. In a bit of a twist, Flash (the real one) is visibly troubled by this.
* ''ComicStrip/ModestyBlaise'':
** When captured by terrorists and forced to call Modesty, Willie addresses her by name instead of calling her "Princess". She immediately packs her bags and comes to his rescue.
** Modesty & Willie also repeatedly use a pre-arranged distress code throughout the series. If either of them drops the name "Jacqueline" into a communication, that's the cue to hit the panic button.
** They also use "Bertha" as code for "I need a distraction".
* Captured by the Mekon and forced to broadcast a message to Earth, Digby claims he's having such a nice time it reminds him of a holiday he once had. His aunt realises he's referring to an occasion when he was wrongfully arrested and that he and ComicStrip/DanDare are being held against their will.
* In a ''MickeyMouse'' story a famous opera singer suddenly not only abandons his contract but signs on for a rival -- and refuses to see anyone. His former studio, not being idiots, finds this suspicious, but have no proof. When he releases a "greatest hits" collection, however, one word in each of the famous arias ([[GeniusBonus all spoofs of real ones]]) is wrong -- and the wrong words together spell out the location where he is held against his will. This trope truly enters when his ex-manager points out he would never miss a word like that.
* In Creator/FrankMiller's first issue of ''Comicbook/{{Daredevil}}'', ComicBook/{{Elektra}} forces a {{Mook}} to phone his boss and set up a meeting (so she could capture him and collect his bounty). The mook suggests a time an hour later than previously planned, which was their codeword for trouble. His boss knew he was going to be walking into a trap.
* In one issue of ''ComicBook/DoomPatrol'', Larry figured out that the putty-like Madame Rouge was impersonating the Chief when "he" called Rita Elasti-Girl -- "the Chief would NEVER call Rita by that freak name!"
* ComicBook/{{Batgirl}} (Barbara Gordon) and ComicBook/BlueBeetle (Ted Kord) [[http://scans-daily.dreamwidth.org/868616.html know each other well]]. A robot impersonates his voice, yet "Babs, fortunately, is no fool, and knows Ted far too well to fall for that shit."
* During the "Operation: Zero Tolerance" [[ComicBook/XMen X-Men]] arc, [[BigBad Bastion]] is psychologically torturing Jubilee by forcing her to watch (faked) images of her fellow X-Men being tortured and killed. Jubilee seems about to break down until she hears "Wolverine" begging for mercy. At this point, Jubilee snaps out of it and laughs in Bastion's face, because she knows that Wolverine would ''never'' beg.
* As the title character and his lover/accomplice are [[MasterOfDisguise Masters of Disguise]], this tends to happen from time to time in ''ComicBook/{{Diabolik}}'', as Diabolik doesn't always know everything. The funniest instance is when Diabolik replaced a GrumpyOldMan and a group of children recognized him ''because he wasn't grumpy enough''.
* Darkly averted in ''ComicBook/TheTransformersRobotsInDisguise''. [[spoiler:In the season one finale it's revealed that Prowl's apparent [[JumpingOffTheSlipperySlope descent into villainy]] was actually a result of Megatron's Loyalists mind-controlling him. However ''none'' of the protagonists had figured this out beforehand; in other words, they thought him becoming a ruthless murderer was completely in-character. Once he's rescued, the realization that none of the Autobots actually trust him utterly breaks Prowl's heart, causing his SanitySlippage to kick into high gear.]]
* Invoked in ''ComicBook/CleanRoom'' and its version of demonic possession. One demon uses singsong repeated consonants that give away its presence in a host to the audience, if not the characters.
* In ''Comicbook/NightwingRebirth'' #27, Spyral have turned evil (again) and Nightwing and Huntress are facing a squad of agents led by Dick's old friend from ''Comicbook/{{Grayson}}'', Tiger. Dick wants to find evidence this isn't what it looks like and jokingly says "He hasn't called me an idiot yet, are we sure it's really him?" [[spoiler: At the end of the issue Nightwing finds Tiger standing over another, badly beaten Tiger, who manages to mutter "you ... idiot ..."]]
* ''ComicBook/TeenTitansGo'': In Issue #42, after [[spoiler:the Teen Titans think they got all parts of Raven's personality back, Robin finds it odd "she didn't so much as frown at Beast Boy" for causing that mess in the first place. The Trigon-eyed Raven is still at large and shows a [[SequelHook "the end?" sign]].]]
* ''ComicBook/ThePunisherMAX'': In the final arc, Elektra calls the Kingpin to let him know she's killed Frank. Fisk, who knows she'd be a lot more elated at having killed the Punisher, instantly deduces Frank has a gun to her head and tells her to put him on.

[[folder:Fan Works]]
* In ''Fanfic/FaithAndDoubt'', it's revealed that Chrysalis' poor impersonation of Princess Cadance was due to the Princess acting like [[PrinceCharmless Prince Blueblood]] when she was caught, hoping it would clue others in. Chrysalis falls for it, but it fails to alert Celestia, due to her immense blind spot for her family.
* ''FanFic/TheTwilightChild'': Rarity notices something's up with Rainbow Dash when she starts enunciating properly. This is because Rainbow Dash [[spoiler:has been on the receiving end of a FreakyFridayFlip.]]
* In ''Fanfic/OutOfTheDeadLand'', Steve tells Bucky that the thing that tipped him off to him having been replaced by a robot impostor was that the robot told Steve only what he wanted to hear whereas the real Bucky wouldn't have gone along with everything he wanted unless he was up to something. There's also a bit of {{Irony}} at work here, as the last thing the real Bucky told him before being kidnapped was that he ''[[ThatManIsDead wasn't]]'' Bucky (due to suffering from a brainwashing-induced identity crisis) but that Steve detected it as still more authentic than the false Bucky apologizing and telling Steve that he'd work harder to be Bucky.
* The "Setting the Curve" chapter of ''Fanfic/TheMysteriousCaseOfNeelixsLungs'' has the ''Voyager'' and ''Vetar'' crews hunting a [[Series/StarTrekDeepSpaceNine Founder]] that got trapped in the Delta Quadrant with them. At the climax it tries to hide as ex-Maquis ''Voyager'' crewman Tahel Mizrahi, but Ayala identifies it because Mizrahi was born and raised an Orthodox Jew in Israel and hasn't used the word "Jesus" as an exclamation as long as he's known her.
* ''Fanfic/ThisBites'':
** The SelfInsert character Cross outs Mr. 2 from his disguise by insulting Emporio Ivankov.
-->'''Mr. 2''': ''[[BerserkButton THAT'S A BARE-FACED LIE!]]'' ''([[OhCrap stricken look]])''
** Zeff realizes something's dreadfully wrong [[spoiler:[[Anime/BaronOmatsuriAndTheSecretIsland on the Secret Island]] when he hears Sanji refuse someone food]]. And that's just one of the alerts.
-->'''Zeff''': Sanji... he would never say that. Not in a thousand years, not if his life depended on it, not if every woman in the ''world'' begged him to say it.
** Cross invokes this again: by convincing Iceburg and Franky that Robin has never wanted to revive the Ancient Weapons, they decide that they don't need to keep the Pluton's blueprints around anymore... forcing the two hidden [=CP9=] agents to make a grab for the blueprints once Franky brings them out to burn them.
* ''FanFic/RosarioVampireBrightestDarkness Act IV'': The gang, especially Moka and Mizore, are able to tell right away that Felucia has been BrainwashedAndCrazy by Hokuto when she constantly goes on rants about how Dark abandoned her to be regularly tortured, both physically and sexually, by Hokuto's PsychoLesbian CoDragons, Jovian and Jacqueline; they know that the real Felucia has UndyingLoyalty to Dark and would ''never'' lose faith in him.
* In ''Fanfic/BringMeBackHome'', Bridgette, while forced to impersonate her parallel universe counterpart Marinette, shocks Marinette's friends when she dismissively refers to Chat Noir as "like a sidekick" and not as important as Ladybug. This is something Marinette would ''never'' say, in or out of costume.
* Spoofed in ''WebVideo/DragonBallZAbridged'', where 18 is tipped off because Cell's impression of 17 is so TotallyRadical that it's almost physically painful ("Yo shiggy-diggy, what's up my sizzle?")
-->'''Fake 17:''' So what you need to do is calm down and get all up in Cell! It's downright tubular in here! We got candy and puppies andó\\
'''18:''' You know absolutely nothing about us, do you?\\
'''Cell:''' Okay. To be fair, I just met you.

[[folder:Film -- Animation]]
* ''WesternAnimation/{{Ice Age Continental Drift}}'': While Manny, Sid, Diego, and Granny are sailing over the night in Captain Gutt's stolen ship trying to return home, they encounter mythical sirens who hypnotize them by shapeshifting into the characters they are in love with (Ellie and Peaches in Manny's case; Shira in Diego's case; a gorgeous female sloth in Sid's case; and a hunk male sloth in Granny's case). Fortunately, Manny snaps out of it when the Ellie-shaped siren tells him he is always right which the real Ellie would never say and immedately changes the direction of the ship saving their skins at the last second.

[[folder:Film -- Live-Action]]
* In the war film ''Film/TheBigRedOne'', some German soldiers are posing as Americans. They're found out when somebody notices that throughout their meal they hold the fork in the left hand and the knife in the right instead of cutting off a piece of meat then transferring the fork to the right hand to lift the food to their mouth.
* In ''Film/TheBourneUltimatum'', when [[spoiler:Nikki is in a room with Jason Bourne and asked to "code in" on the phone to her superiors. Her personnel record is shown on screen, with responses for "normal" and "under duress", but despite being in a potentially dangerous situation she gives the "normal" response. This was because she'd switched sides]]. However, [[spoiler:her superiors figure out Bourne is there anyway and send troops in to get him, and both Bourne and Nikki know it, despite her giving the "normal" response]].
* ''Film/{{Bullshot}}'' (1983). The dastardly villain, Count Otto von Bruno, who speaks in a [[UsefulNotes/{{Prussia}} stereotypical Prussian accent]], fakes the voice of Professor Fenton with AppliedPhlebotinum. Despite a [[FailsafeFailure chronic malfunction]] which forces von Bruno to speak at a vastly sped-up rate, the Professor's [[DamselInDistress dim-witted daughter]] doesn't suspect a thing when he says: "I want you the formula to London bring." Only our hero Bullshot Crummond realises instantly that you'd never hear a split infinitive from an Oxford man, and so it must be a trap!
* In ''Film/CopsAndRobbersons'', Creator/ChevyChase's character Norman is a huge fan of cop shows and has always dreamed of being a cop (except his ideas of what it means to be a cop come exclusively from TV). After the cops discover that a meeting between criminals is going to take place next door to his house, detectives Jake and Tony set up a stakeout in Norman's house, much to his delight. Jake is initially annoyed at Norman's assumptions about cops, especially when Norman interferes in Jack's duties. However, when the bad guys take Norman's family hostage, Norman calls his own house (not knowing the situation), and Jake tells him a message involving time. Norman is confused, but then looks up police codes and figures out that there's a hostage situation at his house. Unfortunately, instead of calling the police like Jake wanted, Norman decides to rescue them himself.
* In ''Film/DieHardWithAVengeance'', a bunch of German mercenaries impersonate cops. Although the leader speaks English with a flawless American accent, he slips up on a few word choices, such as calling an elevator a "lift" and saying that it's raining "dogs and cats", instead of the usual "cats and dogs". When [=McClane=] recognizes that one of them is wearing a friend's badge, and mentions the lottery to figure out if anyone on the elevator is real. None of the fake cops know last night's numbers, though in the beginning it's established that every NYPD cop plays the lottery and knows exactly what the winning numbers were.
* In ''Film/FromRussiaWithLove'', James Bond chastises himself for not recognising an enemy agent when the man orders the wrong wine with a fish course at dinner. Unfortunately, Bond only realises this hideous faux pas after the enemy has him at gunpoint.
* In ''Film/ItCouldHappenToYou'': When a cop walks into a local deli to get coffee, he asks where the owner's wife is. The owner tells him that she's out sick, but as he turns to get supplies we see that his wife is being held at gunpoint by a robber. Knowing that the cop can't see this, he then gives him the coffee for free. Sure enough, when the cop he goes outside to join his partner, he tells him that the man is being robbed -- aside from the free coffee, having come to the store for years, they know that "that bitch would show up for work even if she were dead".
* In the second ''Film/LaraCroftTombRaider'' movie, Lara's butler tries to do this, but is rebuked for it. "Why are we even having this conversation?"
* Happened in the second ''Film/MissCongeniality'' movie.
** Miss United States drops a big hint to her location by saying "My booty is on the line here." Sandra's character catches on and explains that "She would never refer to her butt as her booty... she would never refer to her butt as her butt! She calls it a po-po!" The kidnappers tie her and the celebrity pageant host into the sinking ship at Treasure Island in Las Vegas to passively kill them.
* ''Film/MortalKombat'': During the final showdown, [[BigBad Shang Tsung]] pulls a ShapeshifterGuiltTrip against Liu Kang by morphing into his brother Chan, who Shang Tsung had murdered. Though Liu knows it's not the real Chan (after all, Shang morphed ''right in front of him''), he's still hesitant to attack until Shang!Chan says he forgives Liu for letting him die. Though Liu [[ItsAllMyFault blames himself for Chan's death]], he knows that Chan himself wouldn't... and hearing this gives him the right state of mind of who's ''really'' to blame:
-->'''Liu Kang''': No....it wasn't my fault! Chan chose his own path...every man is responsible for his own destiny. ''Shang Tsung killed my brother!''
* ''Film/NationalTreasure2BookOfSecrets'':
** The trap is somewhat different. Mitch Wilkinson forces Emily Appleton to give her ex-husband a rather unconvincing fake translation of some Olmec hieroglyphs. He doesn't seem to pick up on her gestures, so she promptly texts her son Ben Gates the real translation.
** She also deliberately starts a fight with her ex-husband, mentioning a place seemingly from their past. Except it's a subtle historical reference that only her ex-husband and son (and her son's ex-girlfriend) could figure out.
* ''Film/{{No Man of Her Own|1950}}'': This happens constantly to Helen as she tries to pretend to be Patricia Harkness: she doesnít know Hughís (Patricia's husband) favourite song, didnít know that Hugh had a brother (Bill), and signs her real name when trying out a pen out of habit. The Harkness family (who had never met or seen a picture of Patricia) think this is just a result of the train accident, but Bill is the only one that figures out that Patricia isnít really Patricia. [[spoiler: But he doesnít care.]]
* In ''Film/TheOneILove'', Ethan realizes that the Sophie he's talking to in the guest house isn't his actual wife when she cooks him bacon, because the real Sophie would never let him eat bacon. [[spoiler:It's also what tips him off to the fact that the Sophie who escapes with him at the film's end isn't the real one.]]
* In ''Film/TheRingTwo'' [[spoiler:"Aiden" refers to Rachel as "mommy", when he prefers to call his mom by name.]] This clues her in that he is being possessed.
* The ''Series/{{Firefly}}'' movie, ''Film/{{Serenity}}''
-->''Mal and Inara have a polite, awkward conversation by videophone, with Inara inviting Mal to visit her. Discussion with the rest of the crew ensues.''\\
'''Zoe''': So. Trap?\\
'''Mal''': [[ObviousTrap Trap.]]\\
'''Kaylee''': How do you know Inara don't just wanna see you? People do have feelings. I'm referrin' here to ''people''.\\
'''Mal''': Y'all were watchin' I take it?\\
'''Zoe''': Yes.\\
'''Mal''': [[BelligerentSexualTension You see us fight?]]\\
'''Kaylee''': No...\\
'''Mal''', ''matter-of-factly'': Trap.
* In ''Film/SherlockHolmesAGameOfShadows'', after an action sequence that separates the pair, Mary is understandably confused when Watson sends her a letter saying he doesn't miss her and hopes to never see her again. Mycroft Holmes tells her the truth can be found from a code that he and Sherlock devised as children, where a notice would be taken at face value or as the complete opposite depending on if the first letter of the note was a consonant or a vowel; in this case, Watson's letter is of course the complete opposite of what he means. The letter needed to be coded in case it were intercepted by someone affiliated with Moriarty, who had just targeted Mary in his scheme just to spite Sherlock Holmes.
* In ''Film/{{Sneakers}}'', Crease draws Brice away from a meeting with the villains in a public meeting space after seeing a newspaper blurb mentioning that the mathematician they had stolen the MacGuffin from has been killed and realizing what their employers really are. He gets Brice to leave with him by holding up the carphone and shouting that it's his mother calling. Since Brice's mother would have no way of calling him, and one of their group has the nickname "Mother", it's a clear signal that he needs to get out of there.
* In ''Film/TheStranger'', Franz Kindler (Creator/OrsonWelles) is an escaped Nazi war criminal living in the United States under a fake identity. He's at a dinner party that also includes Mr. Wilson, a war crimes investigator who suspects that Welles's character might be the missing Kindler. A casual discussion of the German character turns to Karl Marx, which leads Kindler to respond by saying "but Marx wasn't a German; Marx was a Jew." This causes Wilson to realize that "Charles Rankin" is in fact the man he's been hunting.
* In the movie ''Film/SuddenImpact'', when Harry gets his usual morning coffee, the café is being robbed; everyone is being forced to act naturally, but the waitress (knowing Harry's usual is "no sugar, no milk") adds ''lots'' of sugar. Harry, distracted by some case work he's going over, just pays and leaves with the cup. Outside, he takes a sip, spits it out and turns back to the diner.... then notices "patrons" locking the doors and turning the "Open/Closed" signs around, figures out what's up, and goes around to come in through the back.
* In ''Film/SupermanII'', the Krypton criminals led by General Zod force their way into the White House. They enter the Oval Office, and ask the person sitting behind the desk to kneel before Zod, which he does without saying a word. Immediately, they decide that he is not the President, since someone with that high a rank would put up ''some'' resistance.
* In ''{{Film/Surrogates}}'' Creator/BruceWillis' character is tipped off that his partner's surrogate isn't being controlled by his actual partner when she refers to him by his last name. Everybody else in the movie does this, but she always called him Tom.
* ''Film/Terminator2JudgmentDay'' does this twice, first when John tries to call his foster parents to warn them about the T-1000:
-->'''John:''' Something's wrong, she's never this nice.
** At which point the Terminator takes over:
-->'''The Terminator:''' ''[to John]'' What's the dog's name?\\
'''John:''' Max.\\
'''The Terminator:''' ''[in John's voice]'' [[BluffTheImpostor Hey Janelle, what's wrong with Wolfie? I can hear him barking.]]\\
'''"Janelle":''' Wolfie's fine, honey, Wolfie's just fine. Where are you?\\
'''The Terminator:''' ''[hangs up the phone]'' Your foster parents are dead.
** It happens again when the T-1000 takes Sarah Connor's form and asks for help, something the real Sarah had previously berated her son for doing. The other Sarah instead tells John to get out of the way, something the T-1000 would not be inclined to tell his target.
** In the DirectorsCut, however, John is tipped off when he sees his "mother's" foot melting into the floor.
* In ''Film/ThorTheDarkWorld'', a savvy viewer will realize early on that [[spoiler:Loki's betrayal of Thor to the Dark Elves is an act.]] When doing so, he introduces himself as "Loki of Jotunheim". While he actually ''is'' a Jotun, he despises his birthplace and his birth parents, and whatever his issues with his adoptive family, he still considers himself to be Asgardian. Without that little hint, Loki's deception is extremely convincing.
* In ''Film/{{Transcendence}}'', Max quickly begins to suspect something's gone wrong with Will's upload when he's asking for access to financial and educational data almost immediately after he regains his sense of self. The Will he knows was never so proactive, which convinces him that this Will is just an echo superimposed over the PINN AI used as the base for his program. [[spoiler:It turns out that Will's actions are entirely in-character, but now he has the means to achieve his goals instead of being content with limited gestures.]]
* In ''Film/TheWorldsEnd'', Andy realises that [[spoiler:Oliver]] has been replaced when [[spoiler:Blank!Oliver]] doesn't react to a hated childhood nickname, or to to references about [[spoiler:Gary having sex with Oliver's sister, Sam]].
* ''Film/XMenFilmSeries'':
** ''Film/XMen1'': For the audience at least, "Bobby Drake's" stern demeanour when he tells Rogue that she should go is at odds with his introduction as a NiceGuy. As it turns out, Mystique had impersonated him.
** ''Film/XMenFirstClass'': How kid Xavier pierces kid Raven's disguise at the beginning of the film. She looks like his mother, but acts nothing like her. He confirms it with telepathy.
** ''Film/XMenDaysOfFuturePast'': Dr. Bolivar Trask's secretary is surprised when he compliments her scarf, which is something he doesn't normally do. We learn a few seconds later that "Trask" was actually Mystique, who hasn't quite mastered gender roles yet.

* ''Literature/{{Animorphs}}'':
** When Jake is infested, his friends are convinced he has been body snatched when he shows sudden, inexplicable revulsion to Ax's touch and calls him "Andalite filth", confirming the suspicions. Of course most of the time the trope is subverted with Yeerks impersonating humans flawlessly.
** And then he flubbed it ''again'' by trying to weasel out of having to stay in the cabin for three days to starve out the Yeerk. It's pointed out that the ''real'' Jake would have gone along with the plan, no matter the potential for disaster, just to make ''absolutely'' sure that there was no Yeerk. At that point, the Yeerk really knows he's screwed.
** That particular Yeerk seems to be a bad actor; he was also Tom's original Yeerk, who quit the basketball team and thus clued Marco in that Tom was NotHimself.
* John Birmingham's ''Literature/AxisOfTime'': A [[TimeTravel temporally-displaced]] multinational fleet from 2021 and the US Pacific Fleet of 1941 have just engaged in battle by accident, and are trying to sort out the situation. One of the 1941 sailors volunteers to go over to the future fleet, and arranges a duress signal with his superiors by suggesting "My sainted mother taught me never to swear, so if anything is wrong, I could slip in a fucking profanity, sir."
* In ''The Bet's On, Lizzie Bingman'', the titular character is kidnapped because she witnessed a murder. While she's leaving with the murderer she manages to alert her friend because she mentions her sisters: Lizzie only had brothers.
* Detective Elijah Baley is informed that his wife Jessie is a member of a criminal organization in ''Literature/TheCavesofSteel.'' He knows it is a lie because her name is given as Jezebel, a name she never uses.
* Creator/AgathaChristie:
** In the short story "The Adventure of the Sinister Stranger" uses a {{Homage}} to the [[WeirdAlEffect now-obscure]] Oakwood Brothers stories by Valentine Williams. When Tommy announces he is going to "walk into a trap with my eyes open", Tuppence says that this is exactly what happens in the stories when Desmond Oakwood blunders into something and needs Francis to rescue him. Tommy subsequently signs a letter asking Tuppence to return to the agency "Francis", to signal that he's done precisely that.
** In ''The Secret Adversary'', Tommy realises that a message sent to him from Tuppence is not actually from her, as it is signed "Twopence".
** Also used in the novel ''The Man in the Brown Suit''. After Anne is lured into a trap by a note allegedly sent by Harry, she and Harry decide that in all future written communication, they will only refer to each other by pseudonyms. Later, Anne is kidnapped and forced to write Harry a note which will lead him into a trap. When she signs it with her real name instead of the agreed-upon pseudonym, Harry recognizes that the note is a fake and that Anne is in trouble.
** This also shows up in "The Flock of Geryon," one of the twelve short stories in ''The Labours of Hercules.'' The "flock" of the title is a religious cult that has been connected to the deaths of three elderly ladies; Hercule Poirot teams up with Amy Carnaby, an easily flustered but brave middle-aged woman, to solve the crime. Mrs. Carnaby infiltrates the cult and later meets Poirot for tea; at the end of the meal, she abruptly stands up and announces that she is giving up on their plan, as she has become completely devoted to "the Master" and would do anything for him. Poirot immediately realizes that something is wrong, as Mrs. Carnaby openly stated her utter disdain for the cult at the beginning of the story. It turns out that she recognized that the cult's caretaker was secretly eavesdropping on their conversation from the next table, and she quickly improvised the speech to alert Poirot.
** Another short story about a woman who realizes her husband is a serial murderer sees her using a phone to call a local friend for help. As her husband is sitting in the next room, she pretends to be calling in an order to the butcher's. She holds the conversation, but only presses down on the phone's receiver switch (which makes the other person hear what she's saying) when relaying information about her situation (e.g. "I need four pork chops"--press--"it's VERY IMPORTANT"--release--"we're having company tomorrow, so it's almost"--press--"a matter of LIFE AND DEATH..."). The woman's husband is slightly suspicious, but she allays his fear by claiming that she was just being melodramatic to get results.
* In the Alistair Maclean spy novel ''The Dark Crusader'' (also known as ''The Black Shrike'') the hero includes the nonsense word 'Bilex' in all communications with headquarters, to show that he is ''not'' sending under duress. When he is captured, the bad guys tell him that they have sent a message assuring HQ that all is well. At the end of the book [[spoiler: he realises that either this message (minus the safety word) was never sent or it was ignored by his superior. Either way, it proved that the superior was actually in league with the bad guys.]]
* In ''Literature/ADarkerShadeOfMagic'', a villain tries to get the drop on Kell by magically disguising herself as Lila, only for Kell to immediately stab her. He later tells Lila he knew it wasn't really her because the villain used the word "please".
* ''Literature/{{Discworld}}'': While Magrat is hiding from vampires in ''Discworld/CarpeJugulum'', "Nanny Ogg" speaks to her through the keyhole... and Magrat asks her to tell a particular dirty joke. The voice hesitates and says that now isn't the time, which alerts Magrat that it's really one of the vampires -- so when the vampire tries to come through as steam, it winds up in a jar full of lemons.
* ''Literature/TheDresdenFiles'': In ''Literature/BloodRites'', after the two of them are captured by the BigBad, Lord Raith, Murphy calls Harry "Mister Dresden". Raith dismisses it without a second thought, but Harry immediately picks up on it as her intentionally playing up being helpless, as it went against both the [[VitriolicBestBuds nature]] of their friendship and her strong, assertive personality.
* In ''Literature/EndersGame'', Ender gets a message that really ''was'' written by his sister Val, but he figures out that something is off about it because of how aggressively she inserts personal anecdotes and jokes into the letter in an apparent attempt to prove that it's really her. Ender correctly guesses that she would be much more subtle, so the military must have told her to write it.
* Georgina "George" Kirrin in the first ''Literature/TheFamousFive'' novel is ordered to send a note to two of the gang (another is with her) by some smugglers. She signs it "Georgina", which she would never call herself and gets highly offended when called that.
** Again with another Enid Blyton story: in "Five Find Outers and Dog" Frederick Algernon "Fatty" Trottville is made to sign a letter by people holding him hostage. He is forced to sign as "Freddie" which makes Bets and them all suspicious.
* In ''Literature/{{Fearless}}'', there's a StoryArc where Gaia is being forced to humiliate Ed Fargo. He asks her "You're enjoying this aren't you?" and Gaia answers, "Yes, I like torturing you. Almost as much as I like Lox." In this case, she's doing it deliberately as a secret code (she'd told Ed earlier in the book that she hated Lox).
* In a nod to ''StarTrek'', the ''Literature/FightingFantasy'' novel ''Starship Traveler'' has a part where you're captured by aliens and cloned, and the clone tries to impersonate you so the aliens can steal your ship. If you succeed on a roll, you can with great mental effort implant two things into the clone: an inability to lie, and the name of a certain sterile prison planet back in your own universe. When the clone tries to get your crew to beam down and get captured, he'll tell them that it's lovely down there, "as nice as [prison planet]".
* Several characters in Creator/FrederickForsyth books use this when communicating from behind enemy lines. One trick is to always include a line of very slightly misquoted poetry -- if a poem's quote is ''correct'', it means he is operating under duress.
* In Literature/GauntsGhosts, the resistance on Chaos-occupied Geron respond to the code phrase "Geron survives" with "Despite their efforts" normally, while under duress they say "Even though it dies."
* In ''Literature/GreenRider'', a man hides a crucial message in a love letter. He's killed before he can deliver it, but the protagonist, Karigan, passes on the love letter to the messenger's girlfriend. When she gets the letter, she spots some inconsistent details (he misstates the color of her hair; he mentions a brother when he doesn't have one) and mentions it to Karigan, who realizes that the letter contains a coded message.
* In Creator/DianeDuane and Peter Morwood's ''High Moon'', the bad guys fake a message from the protagonists' superior officer to get them out of the way. They're briefly deceived, but then notice that it's signed in a nonstandard way, the routing makes no sense, and most importantly that this message from their cost-focused boss doesn't say a thing about the expensive reward they just authorized.
* ''Literature/HonorHarrington'': Towards the end of ''On Basilisk Station'', Honor begins to suspect something fishy going on with a Havenite flagged freighter, the ''Sirius'', that's been orbiting Basilisk since she got there. It's ostensibly [[FakingEngineTrouble waiting for parts for its Warshawski Sails]], but Honor's crew notice its impeller nodes are active, and have been the entire time, meaning it could quickly bring up its impellers and get under way, but would also increase wear on the nodes themselves, not something a freighter captain would normally do, but it is something a warship captain might do. [[spoiler:''Sirius'' turns out to be a Q-ship, a warship disguised as a freighter. ]]
* Lieutenant Eve Dallas from the ''Literature/{{In Death}}'' series hates being affectionate with her husband in public, especially when she's working. She never uses pet names or overly flowery talk, so when she does, it's her way of telling her husband Roarke something's wrong. Used most recently in ''Obsession in Death'':
-->'''Eve:''' So you broke my clever code?\\
'''Roarke:''' "Later, honey?" I should say.
* In the Literature/JackReacher novel ''Tripwire'', his girlfriend has been captured and been ordered to lure him into a trap. She calls him up and opens the conversation with "Hi, Jack". The point is that the main character is ''always'' called Reacher, by everyone including his mother when he was very young, and no one ever uses his first name. The coincidence of "Hi, Jack" and "hijack" only makes it more convincing that this is indeed a trap.
* In ''Literature/JenniferTheJerkIsMissing'', there is an unusual variant of this. To find out if Jennifer-the-Jerk Smith made it to camp or was kidnapped before reaching it, the protagonist, Amy, calls the camp to see if Jennifer Smith arrived. She's told that yes, Jennifer Smith did indeed arrive, and she's a very pleasant and charming girl. Malcolm, the kid who suspected the kidnapping in the first place, immediately recognizes that Jennifer-the-Jerk Smith is neither pleasant nor charming, and therefore the girl that arrived couldn't have been her. (She wasn't)
* In the Literature/JoePickett novel ''In Plain Sight'', Sheridan does this after she and her sister Lucy are kidnapped and she is forced to call her mother to say that she and Lucy are going to a friend's place after school. She does so by saying that Lucy can't talk because her mouth is full because she is eating her lunch early as she always does (Lucy refuses to eat and usually brings most of her lunch home with her) and that she is calling on her cell phone (Sheridan doesn't have a cell phone).
* In the second ''Lady Grace'' mystery, Lady Sarah is abducted by a sea captain, and alerts Grace -- or anyone -- who can help with a message passed by a commoner that she sends her love to "Lady Jane, my dearest friend". The two young women hate each other with a passion, and so Grace and Masu are off to the rescue in a trice.
* ''Literature/LemonySnicketTheUnauthorizedAutobiography'' features a long and poignant letter written by the Duchess R to Lemony Snicket. He immediately lambasts the numerous errors she would never have made. [[spoiler:Or, errors she might have made as a coded signal that all was not well.]] [[spoiler:Or, errors she might have made due to disruptions in her training which were caused by constant moving of the V.F.D. Headquarters.]]
* In the ''Literature/{{Lionboy}}'' series, the main character knows his parents are in trouble because their letter to him is written the way an adult talks to a child, while his parents always talk to him like he was older. He and his parents use this in all their communications throughout the series.
* In one ''Literature/MaximumRide'' book, a clone of Max tries to take her place. The kids realize something is up when she offers to cook (as Max is a LethalChef and leaves the cooking to Iggy), and when she expresses surprise that Iggy would know his way around considering that he's blind. Of course, Angel can read minds, too, which the clone has no clue of, so ''she'' knew right away.
* In a Literature/NancyDrew book, a young woman on the phone with Nancy asks her to "tell Ned I'll see him at the big rally on Monday". There is no rally on Monday -- the girl is trying to tell Nancy and Ned that she's in trouble. Unfortunately, Nancy doesn't realize this and thinks the girl is trying to say she's ''okay'', and as such, doesn't relay the message to Ned...
* One of these is part of what kicks off the plot in ''Literature/ReconstructingAmelia''. The official report of the titular Amelia's death is that she was caught cheating on an English paper by submitting a plagiarized paper from the Internet, which spurned her into an impulsive suicide. Her mother Kate, however, never ''quite'' buys into this story, despite a lot of the evidence pointing that way, because Amelia would never cheat -- especially not on an ''[[CuteBookworm English]]'' paper. When she receives an anonymous text telling her Amelia didn't actually kill herself, she begins investigating her daughter's death. [[spoiler:She's right -- Amelia was actually pushed, and the so-called cheating was actually a FrameUp. Kate finds her real paper and uses it to clear Amelia's name.]]
* In the Creator/TomClancy[=/=]Larry Bond novel ''Literature/RedStormRising'', Air Force weatherman Mike Edwards, stranded on occupied Iceland and radioing NATO everything he sees, is given a Duress Code. Played with in that he nearly says it by mistake. (If captured and made to phone in phony reports, he is supposed to preface the message with "Beagle Calling Doghouse, things are going great.)
** In the ''Op Center'' novel ''Games of State'', a character is forced to send a message back to their MissionControl as part of the villains' plan. As is explained [[UnspokenPlanGuarantee later]], he had a pre-existing arrangement where every message he sent would include either a smiley face[[note]]:)[[/note]] or a frownie face[[note]]:([[/note]] depending on whether he was fine or under duress. In this case, it is treated as a characteristic bit of paranoia [[ProperlyParanoid that had eventually paid off,]] rather than anything that an agent would normally do.
* In the ''Rugrats'' novel ''Prince Chuckie'', Tommy and the other Rugrats are able to determine that Chuckie has been swapped with a young prince who looks exactly like him when they realize that he's doing things that Chuckie would never do, as well as the fact that he's lacking the scars that Chuckie had received prior to the novel.
* ''Literature/ASeriesOfUnfortunateEvents'' presents a written variant in the third book. The trio's Grammar Nazi auntie leaves them what looked like a suicide note, but was filled with mistakes, leading them to deduce that it was written under duress and contained some hidden message. Which it did: the letters involved in the misspelled and malformed words spelled out where she was actually hiding.
* In the science fiction novel ''Literature/SewerGasAndElectric'', one of the main characters (a parody of Creator/AynRand's heroes) is forced to play a twisted computer game against a robot double of himself, with his parents' lives at stake. When his ex-girlfriend charges in with a gun to rescue him, the fake jumped up and acted relieved, whereupon she gunned it down. The real one was so absorbed in the game that he didn't even ''notice'' any of this until several turns later, when he realized his opponent hadn't made any moves.
* ''Franchise/StarWarsLegends'':
** In ''Literature/HanSolosRevenge'' when Han and Chewie were to make a smuggling drop, if during the meeting Han did ''not'' try and signal Chewie (who was overseeing the proceedings back in the cockpit of the Falcon) then something had gone wrong with the drop.
** In one of the [[Literature/XWingSeries Wraith Squadron]] books, Face, undercover as a stormtrooper so as to steal TIE fighters for their pirate facade, has to speak the password to the supervisor (because the on-duty officer who knows the password can't say it or it would reveal something was wrong, and the one who was supposed to say it was killed during the break-in). He gets away with it thanks to his acting skills and the static disguising his voice...until he makes the mistake of referring (out of habit) to the TIE fighters as "eyeballs" (New Republic slang). He tries to salvage it by [[JustJokingJustification claiming it was a joke]], to no avail.
* ''Literature/TimeMachineSeries: The Mystery of Atlantis'': If you try and tell a suspicious Athens city guard that you are a Scyth, he will promptly quiz you on a piece of Scythian culture (since he is a Scyth himself.) You fail ("What does a Scyth warrior keep tied to his horse's bridle?" No, not flowers. The scalps of his enemies), at which point he decides you're a runaway slave.
* ''Literature/VorkosiganSaga'': In ''Literature/MirrorDance'', Bel Thorne suspects that the "Admiral Naismith" who just boarded the ship is really Mark and not Miles, and confirms it by referring to Mark as Miles's clone in conversation. The real Miles always refers to Mark as his brother and corrects anyone who says otherwise, but Mark doesn't know this and lets it slide.
* In Dorothy Eden's mystery novel ''Waiting for Willa'', Grace travels from the U.S. to Sweden to help her cousin Willa when the latter sends a message signed with her given name, Wilhelmina. Not only does Willa hate her given name and usually refuse to use it, but also the signature is a danger signal she and Grace had worked out some time before. When the kidnapped Willa's captors make her send another message to Grace, assuring Grace that she's all right, Willa signs the second message "Wilhelmina" as well. This makes Grace even more suspicious.
* In ''Literature/WaysideSchool Gets a Little Stranger'', the students' voices are stolen by [[EvilTeacher evil substitute teacher]] [[VoiceChangeling Mr. Gorf]]; when the lunch lady asks how the class is doing from outside the door, Mr. Gorf tries to trick her by using the voices of the students to say that everything is okay. The lunch lady figures out something is wrong, though, when the voice of the meanest student in the class says "Have a nice day!" This ends up being a parody, as not only does she figure out that something is wrong from this, she somehow figures out ''exactly what inconceivably bizarre trouble they're in'' (that a three-nostrilled man was sucking their voices into his nose) and how to save the day. Just from someone being out of character.
* In ''Literature/WorldWarZ'' the Chinese doctor who encountered one of the first victims of the zombie plague had a friend working in the government. This friend was an eternal pessimist; no matter the situation, he'd always assume it was going to get worse. When the doctor tells his friend about the victim over the phone the friend says, "Don't worry. Everything's going to be all right." That's when the doctor knew that things were really bad.
%%* In a short mystery story involving a group of women at some sort of get-together, one of the members sends a note saying she won't be able to make the meeting. The women reading the letter note discrepancies in the letter, each discrepancy referencing a number (including the absent member's middle initial in her signature being erroneously given as "O", which is taken to mean "0".) There are a total of seven errors in the letter, and when the errors are written out in their numerical form, one of the group theorizes it may be a telephone number. It is -- to the police.

[[folder:Live Action TV]]
* ''Series/TwentyFour'':
** Played twice in the first six hours: Kim said "I love you" over the phone to her mother Teri after being kidnapped, and Teri said the same to Jack under similar circumstances. (Amusingly, Teri catches on immediately, while her counter-terrorism-trained husband [[GenreBlindness doesn't notice]].)
** In season 5 of the series, Jack is held hostage by a group of terrorists, and (rather unsubtly) relays a code he knew when he was employed by CTU ("I'm in a FLANK! TWO! POSITION!") to indicate he is transmitting under duress. This enables the strike teams to overtake the terrorists and save Jack... But only after [=McGill=] [[RescuedFromTheScrappyHeap figures out the outdated code]].
* ''Series/AgentsOfSHIELD''
** Baited from Agent 33 (disguised as Melinda May) by Coulson. Coulson offers both to go out for coffee after a mission, to which "May" replies "I thought you'd never ask." Coulson nods with a small smile, then punches her out.
---> '''Coulson:''' May ''hates'' coffee.
* In "You Got to Have Luck", an episode of ''Series/AlfredHitchcockPresents'', an escaped convict holds a woman hostage in her house when the telephone rings. He makes her answer it, and, listening into the conversation, tells her exactly how to answer each question from her mother on the other end. Later, after the guy let his guard down, the cops come busting in and arrest him. It turns out the woman was deaf but could speak without an accent and read lips as well. She was able to repeat what the guy said, but the mere fact that she was able to hold up one end of a telephone conversation tipped off her mother that something was going on.
* ''Series/{{Alias}}'':
** During the second season arc, Sydney and Jack's [[DeepCoverAgent cover]] as agents of SD-6 is in jeopardy. Jack is in the custody of an SD-6 higher-up, ordered to bring his daughter in under suspicion of being moles. He calls Sydney, then tells her to take "surface roads", because of traffic. That's their code for, "we've been discovered, it's not safe."
** Sydney realizes that the fake Francie is an impostor when she offers her some coffee ice cream, something the real Francie hated, and she accepts.
* On ''Series/AllMyChildren'', Julia has been kidnapped by her recently paroled rapist. He orders her to call her boyfriend and tell him everything's okay. When she does, she tells him that she's assisting a woman from her rape survivor group, a "Mrs. Elijah". Elijah is the name of her boyfriend's former neighbor. He instantly realizes that she's being held prisoner in his old apartment.
* ''Series/{{Andromeda}}'' had Dylan Hunt blinking a code with his eyes when he was kidnapped, his ship computer was programmed to detect it.
* ''Series/{{Angel}}'':
** Lorne appears to have pursued a career in show business and is only seen during brief telephone calls for a few episodes, and each time, he asks how Fluffy is doing. The main characters are convinced that his success is just going to his head and that he is constantly snubbing them, but when they finally show up (not even to rescue him, just for a visit), he says, "Fluffy. Fluffy the dog. The dog you don't have. The universally recognized code for "''I'm being held prisoner. Send help!''" Hilariously played off when they got the call originally as they wonder if it's a pet nickname for a member of the crew, and which member that is.
-->'''Fred:''' "You don't think he was referring to anything of mine that's fluffy do you? Because that would just be inappropriate..."
** Also played with in the episode "Double or Nothing" when an old debt of Gunn's is called in (his soul) and he tries to push Fred away with some very mean words in order to spare her the pain of his leaving/death (not clear). Although visibly upset at first, she sees right through this ploy and tell the others he must be in some VERY BAD trouble because Gunn would never really say those things unless he was TRYING to push her away to protect her.
* ''Series/AshVsEvilDead'': In the episode "The Host", when possessed by Eligos, Kelly appears to gave a moment of clarity and begs Ash to MercyKill her. Ash is initially unsure... until "Kelly" asks him to [[DueToTheDead make a cross for her grave]]. Knowing that Kelly is [[AmbiguouslyJewish Jewish]], Ash quickly realizes that it's nothing but Eligos being a {{troll}}.
* Two enemy agents have a machine which will enable them to switch personalities with Steed and Mrs. Peel in ''Series/TheAvengers''. After the man has switched with Steed, he goes to Mrs. Peel's to lure her into the trap. As they are leaving, he addresses her as "Emma", something Steed never did. She notices, but shrugs it off.
* On an episode of ''Series/{{Baywatch}}'', as Stephanie gets into her truck, she's confronted by an escaped convict, who orders her to drive off the beach. During the drive, Mitch radios Stephanie to tell her to return to headquarters. The criminal orders Stephanie to tell Mitch that she has found a lost child and is driving him around to find his parents. Stephanie complies, knowing that the criminal has just [[HoistByHisOwnPetard hoisted himself by his own petard]]--the lifeguards NEVER drive lost children around to find their parents. Policy dictates that they bring the children to headquarters. The criminal's efforts to avoid detection have resulted in him being found out--Mitch instantly realizes Stephanie's in trouble and sends the police to find her.
* In an episode of ''Series/BeverlyHills90210'', Donna is being held prisoner in her room by a would-be rapist. When David shows up at the apartment to apologize to her (they had an argument earlier in the day), the rapist orders her to get rid of him. So from behind a closed door, Donna repeatedly yells at David to leave, but she keeps calling him "Dave", something she's never done before. David realizes something's wrong and manages to save her.
* A variant in the last season ''Series/BuffyTheVampireSlayer'': [[TheSmartGuy Willow]] sees a vision of [[WaifProphet Cassie]], a girl who had died earlier in the season. "Cassie" explains that she's been sent by Willow's dead girlfriend [[KilledOffForReal Tara]], who can't come herself because Willow's being punished for her RoaringRampageOfRevenge against Tara's murderer. At the end of the conversation, "Cassie" suggests that Willow [[DrivenToSuicide kill herself]] so that she and Tara can be together again. Willow instantly realizes that Tara wouldn't send anyone who would suggest that, and the illusion, sensing its mistake, drops any pretense and reveals itself as the season's BigBad, [[spoiler:[[UltimateEvil the First Evil]]]].
* In the first season finale of ''Series/BurnNotice'', Sam provides a variant: in his proof-of-life photo, he makes a strange hand gesture. Michael looks through Sam's old photos and finds a matching pose, realizing that Sam is telling Michael to give up on him. Michael promptly ignores this and rescues Sam anyway.
** In the third season finale, Madeline Westen apparently had a code phrase meaning "stay away" already established with her sons. It was originally meant to indicate that their [[AbusiveParents father was in a drunken rage]], but it also works pretty well when [[spoiler:the FBI is after Mike]].
** In the fourth season episode "Out of the Fire", Michael calls Fiona 'honey' while talking to her over the phone. She then explains that this a code phrase they had during their Belfast days meaning 'something is wrong'.
* ''Series/{{Castle}}'':
** In episode "3XK": Castle is being tied up and held at gunpoint by a killer when his mother calls. The killer forces him to answer the phone and act normal. When Castle ends the call with "I love you", his mother calls Beckett and tells her something must be terribly wrong.
** In a later episode, "Murder Most Fowl", a 12 year old boy was being held hostage, and used the proof of life video his captors took to try to alert everyone to his location. "Don't forget to feed Ace," he says, only his family doesn't have any pets. Ace turns out to be a place, a subway station where lines A, C and E all run. Thanks to Castle's quick thinking and the victim of the week's invention, the kid is rescued.
** Beckett is forced at gunpoint to call Castle and set up a meeting. Castle apologizes for a fight they had earlier about a dinner with their parents that went badly, and Beckett suggests that they should go to a baseball game because it's "something all four of us can enjoy". Castle recognizes this as a distress signal, since the cause of the fight was his mother disparaging Beckett's father's love of baseball.
** Actually justified in a fun way in "Dance With Death". Odette, an heiress, is killed doing a dance show. Beckett talks to people who all note that Odette was a former party girl who only cared about having fun and getting arrested. However, when she survived a train crash a year earlier, she totally changed her attitude, devoting herself to charity work. People believe the crash was a wake-up call with one person saying "It was like she was a totally different person." It turns out she was. Months before the crash, Odette met with stripper Barbara and realized that with some surgery and lessons, she could be the perfect BodyDouble. Thus, Barbara went about doing stuff like court-ordered community service and drug tests while Odette could continue her party life. Odette was the one killed in the crash and as they were the only two people who knew, Barbara realized this was her chance to [[DeadPersonImpersonation live out a rich life]] for real. The crash was the perfect excuse for why "Odette" would have a new attitude and occasionally not remember things and it worked.
*** As it turned out, this also got Barbara killed. When a man from her past figured out the truth, she had to pay blackmail to him. Odette's financial manager saw the money and confronted her, yelling that he didn't help Odette kill her grandfather for his fortune just so she could waste it. When he saw Barbara's shocked reaction, he realized she wasn't the real Odette.
* In an episode of ''Series/CharliesAngels'', one of the girls has been captured and is forced to act on the phone to the others as though everything is OK. She plays along, but drops in a reference to her station wagon, something the Angels are not known for driving.
* ''Series/{{Charmed}}'':
** In the episode "Chris-Crossed", Chris is forcibly taken to the future, and tells the sisters right beforehand, "Looks like Leo's going to have to fix that floorboard without me." They initially misinterpret this to be his final words of defeat, as it seemingly has no relevance to the situation and he hates Leo, until they figure out Chris is trying to get them to put a power-restoring spell underneath the floorboard for him to use in the future.
** Another ''Charmed'' example has Piper being possessed by a demon. Piper warns the demon that her sisters will eventually figure it out, "Or if they don't, my boyfriend Tom will." Piper's fiance (the aforementioned Leo) comes in just then and immediately becomes suspicious when the demon in Piper's body calls him Tom.
** A demon once tried to impersonate Cole, but made the mistake of telling Phoebe the safest place he knew was in the mausoleum. Cole's real "safest place" is [[ThePowerOfLove with her]].
* In "Series/{{Chuck}} versus The Santa Suit", [[spoiler: Shaw]] has taken over Castle and is holding Sarah hostage. In getting an important file, Chuck apparently gets a call from Sarah, but as he's able to deduce, it's just [[spoiler: Shaw]] using a voice modifier. How? Chuck concludes that Sarah would never call him "dear".
* ''Series/CriminalMinds'':
** Reid does this in the episode "Revelations" when he's being held hostage. The killer forces Reid, on a video feed, to pick a member of the team to die. Reid picks Hotch, and mentions a few character flaws and a relevant Bible verse. Hotch realizes that the personality Reid is describing isn't him -- it's a profile they had been discussing earlier. (To prove it, he has everyone on the team list his worst flaws, and none of them agree with what Reid said.) Hotch then looks up the Bible verse, and realizes that the quotation was incorrect. Since Reid has an eidetic memory, he would never quote something incorrectly. The actual passage is a clue to where Reid's being held.
** In an earlier episode, Hotch was uncharacteristically frustrated with Reid's earlier difficulty in the shooting range after they had both been captured. He eventually convinced the UNSUB to let him kick Reid before they both died, which gave Reid a chance to grab the gun in his ankle holster. Later Reid said he'd figured out the plan at the very beginning, making the drawn-out scene unnecessary.
** In the DVD commentary for "Revelations", the writers mused on this swap and eventually agreed that Reid and Hotch have "a very effective spite-based communication."
* In a recent episode of ''Series/{{CSI}}'', Riley calls Greg Sanders by her own name to alert him to the fact that she and Langston were being held hostage (a technique [[ChekhovsSkill established at the beginning of the episode]] in a training roleplay). He replies "Okay, Sanders" to let her know he understands the message.
* In ''Series/{{Dallas}}'', Pam signals to Bobby that something is wrong by telling him on the phone that she plans to spend the evening playing backgammon with J.R. Bobby knows Pam and J.R. hate each other and would never willingly spend the evening together, so he hurries home to find the whole family is being held hostage.
* ''Series/DarkAngel'' uses this in the episode "Rising". When the villains tries to use Original Cindy as bait, she warns Max by referring to her new boyfriend. Original Cindy is a lesbian.
** However, since ViewersAreMorons, they included an earlier scene where she spent like five minutes listing some of her old girlfriends and how she would never ever ''ever'' date a man.
* In ''Series/{{Defiance}}'' Nolan catches on that Datak Tarr is being held hostage when he is perfectly polite to him and freely offers to help with their investigation for no reward. It's unclear if this was an intentional hint on Datak's part or if he was just afraid for his life and not in the mood for their usual arguments.
* ''Series/DoctorWho'':
** In [[Recap/DoctorWhoS9E1DayOfTheDaleks "Day of the Daleks"]], the Third Doctor once told the Brigadier to "tell it to the Marines" over the phone, alerting Lethbridge-Stewart to the danger.
** In [[Recap/DoctorWhoS9E5TheTimeMonster "The Time Monster"]], the Master impersonates the Brigadier in a telephone call to Sergeant Benton. He imitates his voice perfectly but Benton is not fooled because brigadiers don't call sergeants "my dear fellow".
** In [[Recap/DoctorWhoS13E4TheAndroidInvasion "The Android Invasion"]], the Fourth Doctor realizes Sarah Jane has been replaced when the android accepts the ginger pop he offers her, because he knows she hates ginger pop. In fact he figures it out the moment he sees her, because, as he put it, "The real Sarah wasn't wearing a scarf." Him giving her ginger pop is just his way of checking to make sure he's right.
** In [[Recap/DoctorWhoS14E1TheMasqueOfMandragora "The Masque of Mandragora"]], the Doctor figures out that Sarah is under hypnotic control when she asks him how it is that she can understand the local language. He reveals this to her later (after he's broken the hypnosis), explaining that, "It's a Time Lord gift I allow you to share." (this is expanded upon further in the New Series, where it is explained that the TARDIS translates languages through the Doctor's head). The implication is that it's supposed to seem so natural that the companions don't question it. The fact that Sarah ''does'' question it is what alerts the Doctor to the fact that her mind is being controlled by an outside force.
** In [[Recap/DoctorWhoS28E1NewEarth "New Earth"]], Cassandra pulls a GrandTheftMe on Rose. The Doctor doesn't initially suspect anything, even when Rose suddenly kisses him and starts speaking a little strange. However, when they find out that [[spoiler:the hospital is making clones and infecting them with diseases]] and Rose doesn't react with horror, the Doctor knows something's wrong. In this instance the Doctor likely knew all along that something was wrong from all the clues she dropped but assumed that the problem was related to the strange hospital he was investigating rather than a separate entity coincidentally appearing. He mostly plays along with the ruse to keep things going and only openly admits he knows something is wrong when he has exposed the hospital's secret and is talking to someone with answers.
** [[Recap/DoctorWhoS29E12TheSoundOfDrums "The Sound of Drums"]]: Martha Jones figures out that her parents are speaking under duress when her mother tells her that her father is in the same room without so much as a raised voice. Subverted in the same scene when Martha asks her father to just answer "yes" or "no" if there's someone else there. Unfortunately, the someone else can hear both sides of the conversation.
** Inverted when the 10th Doctor spouts phrases against clone Martha in [[Recap/DoctorWhoS30E4TheSontaranStratagem "The Sontaran Strategem"]], (such as "Avanti!" instead of his usual "Allons-y!"), leading to no response. A few times during the episode he can be seen eyeing her as a result of this.
** In "[[Recap/DoctorWhoS33E12NightmareInSilver Nightmare in Silver]], the Cyberplanner [[HydePlaysJekyll impersonates the Doctor]] in an attempt to steal the planet-destroying bomb's remote detonator from Clara. When she asks him to tell her [[TrustPassword something only the Doctor knows]], he begins to charm her, telling her how funny and pretty she is, and how he's starting to like her "in a way that is more than just-", only to be interrupted by Clara smacking him across the face, which brings the Doctor's personality to the foreground again.
-->'''The Doctor:''' AH! Ow, ''ow'', yes! Ah, it's me! That really hurt! How did you know that was him?!\\
'''Clara:''' 'Cause even if that was true -- which it is obviously not -- I know you well enough to know that [[CannotSpitItOut you would rather die than say it]].
* One episode of ''Series/{{Elementary}}'' has an example that refers back to a ChekhovsLecture during the ColdOpen. Namely, Watson complaining she can't read Holmes' texts because he uses too many weird abbreviations. [[spoiler:After the Killer of the Week kidnaps Holmes, she sends a text to Watson from his phone so she won't worry. Watson recognizes it as fake because it didn't read "like a teenager on a sugar high."]] After [[spoiler:Holmes is rescued, he tries to take credit by claiming he deliberately provoked the killer to text Watson]].
* ''Series/EleventhHour'', "Miracle": Creator/PatrickStewart's character realizes that the apparent suicide of a doctor he'd been working with isn't what it seems when, in her suicide note, she bequeaths to him her "geiger counter". At an earlier meeting, she had made a point of her aversion to that term (on account of Hans Geiger's naziism), insisting instead upon calling it a "radiation detector".
* On ''Series/{{ER}}'', as Sam is supposedly escorting a patient and two attendants to an ambulance, she calls Abby "Abigail", something that she (nor anyone else) has never done. In reality, Sam is being abducted by the trio -- they're her sleazy ex-husband and his two accomplices. Abby's confused, but she manages to realize that something's wrong.
* ''Series/{{Eureka}}'':
** When Jack's smart house takes him hostage (along with several other characters), he responds to his deputy's concern with, "Sorry, false alarm. But thanks for coming down, ''Josephina.''" Since this is the only time he or anyone else has called her anything but "Jo", she realizes pretty quickly that something's out of the ordinary.
** And in the season 2 finale, Taggart can tell that [[spoiler:the Eureka computer is faking Fargo's voice because it calls him "Teg", something Jo called him.]]
* On ''Series/FamilyMatters'', Urkel was being threatened by a criminal, causing him to be placed in witness protection, guarded day and night by, among others, Carl. At the end of Carl's shift guarding Urkel, Carl's partner shows up, holding a large handkerchief in front of his face, telling Carl he has a cold. Carl's suspicions aren't raised until he says "see you later" and the criminal replies "yeah, see you" instead of the actual partner's trademark "not if I see you first". Carl then mentions some money he owes him, slides it under the door, then kicks the door in when the criminal bends down to pick it up.
* On ''Series/{{Farscape}}'', episode "I Shrink, Therefore I am". Crichton is returning to [[LivingShip Moya]], which unbeknown to him has been hijacked. He messages the ship:
-->'''Pilot''': Ka D'Argo is currently... helping Rygel with his... laundry. And Aeryn's writing some... poetry.\\
'''Crichton''': Uh-huh. What about, ah... Chiana and Sikozu?\\
'''Pilot''': Enjoying each other's company. Preparing a meal for... everyone but Rygel. He's... not hungry.
** After hanging up Crichton says "something's wrong".
* On ''Series/{{Firefly}}'', in River's backstory, she sends Simon and his family several odd notes referencing events that never happened, which actually contain a complex code intended to alert them to her mistreatment at the hands of the Alliance. Unfortunately Simon is the only one who can understand it.
* In the pilot of the ''Series/{{Flash Gordon|2007}}'' TV series, Flash receives a call from his mother asking him to come home. The viewer is shown his mother being obviously mind-controlled by an alien cyborg in the room. Flash realizes something is wrong when his mother calls him "Flash", which is a nickname that his father gave him, which his mother ''never'' uses, instead calling him by his real name Steven. He does come home, but he's planning for a trap.
* In one episode of ''Series/{{Flashpoint}}'', Parker was held hostage by an ex-cop who had tried to join SRU but failed the psych test, causing his life to spiral down. The ex-cop told Parker to misled his team to a certain room, which Parker complied but added "stay frosty" alerting his team that he was under duress. However, the ex-cop realized it was a distress code when he was watching the security cameras and noticed the team wasn't heading towards the given room.
* ''Series/GameOfThrones'': The generally accepted story at the beginning of the series is that Jon Snow is the son of Ned Stark and an unknown woman he knocked up during Robert's Rebellion. However, Stannis, referencing Nedís honor, remarks on this story, ''"Perhaps, but that wasnít Ned Starkís way,"'' which casts doubt on Jon's true parentage. [[spoiler:Season 6 reveals that Jon is actually Ned's nephew -- he is the son of Ned's sister Lyanna Stark and Rhaegar Targaryen. Ned promised Lyanna on her deathbed that he would take care of Jon and not reveal his true parentage to anyone, including Robert Baratheon, who would have probably killed him. Ned keeps his word, raising Jon as his own and spending the rest of his life protecting him.]]
* On ''Series/GeneralHospital'', when Mac was kidnapped and replaced by a double, he fed him incorrect information about his personal life, resulting in him treating his fiancée like dirt and basically sexually harassing his coworker who had no interest in him.
* ''{{Series/Gotham}}'': In the second season finale, Barbara spots [[spoiler: the fake Jim Gordon]] when that person [[spoiler: shows no fear or distrust of Barbara, instead flirting with her, and bad-mouths his beloved Leslie]].
* ''Series/HouseOfAnubis'':
** Patricia being polite over the phone was enough to let everyone know that she wasn't alone.
** Mara realized something was wrong with Trudy, when in the letter she wrote, she mentioned a relative that Mara knew didn't exist, because Trudy had said before that the students were basically her only family. [[PublicSecretMessage It turns out the letter was literally asking for someone to help her.]]
* In the ''Series/{{JAG}}'' episode "Secrets" in season 2, Admiral Chegwidden is being held at gunpoint, and tells Bud over the phone to get him a specific file. Harm and Mac realize the file the Admiral asked for is about a sailor who held his CO hostage, tipping them off.
* In a first-season episode of ''Series/{{Jericho}}'', Johnston uses this technique to flush out a group of desperate con-artists posing as Marines, by mixing Marine and Army mottos to see if they'd recognize the wrong ones.
* On ''Series/{{Justified}}'' Boyd Crowder calls up his new business partner, Hot-Rod Dunham to finalize the details of a major drug deal. At the end of the conversation, the Hot-Rod tells Boyd that he hopes everything goes as smoothly as the last time he, Boyd and Dickie Bennett did a drug deal together. Boyd instantly realizes that Hot-Rod is under duress and the drug deal is a trap. The last time Hot-Rod bought drugs from Dickie Bennett, things went far from "smooth" because Boyd ambushed them and stole Dickie's money. This was followed by a MobWar that saw many people die.
* Used quite a bit on ''Series/KnightRider'', usually to indicate something very wrong with KITT.
** In the episode "Killer KITT", KITT snapping at Michael was an indication that his programming was being messed with.
** One episode of the new series had a hilarious variation when Mike is impersonating a member of a group [[TheCaper out to steal from a Vegas casino]]. The leader figures out something is wrong because Mike is too ''competent''.
* On ''Series/LaverneAndShirley'', when Shirley needs help after being handcuffed to an escaped bank robber, she calls Mr. [=DeFazio=] at his restaurant requesting "extra BBQ sauce" on her chicken. Naturally, Mr. [=DeFazio=] fails to note Shirley's "code"... although Laverne immediately understands that Shirley would never order extra BBQ sauce, because it would get under her fingernails.
* In the ''Series/MacGyver1985'' episode "Countdown", Mac cues Pete in on the fact that he needs to speak to him on a private channel by 'reminding' him that they are due to play golf when he gets back. Mac has never played a round of golf in his life.
* ''Series/{{Merlin 2008}}'':
** Rather terrifyingly {{inverted}} once. The setup is that [[BitchInSheepsClothing Morgana]] has convinced [[WellIntentionedExtremist King Uther]] that his son Arthur has been enchanted by Guinevere. Convinced that Arthur is under a spell Uther orders Guinevere to be burnt at the stake, at which point a panicking Arthur tells his father that he'd be willing to renounce his claim on the throne if only Guinevere is spared. Unfortunately, Uther takes this as "final proof" that Arthur is under a spell, claiming that it's something that he would never say. Except of course, he ''does''.
** Played straight in a later episode: [[ParentalSubstitute Gaius]] is being controlled by a goblin. Arthur suspects as much and tricks the goblin into revealing itself by discussing [[LikeASonToMe Merlin's]] imminent execution. When goblin!Gaius does not show the least bit of a negative reaction to this, Arthur knows that Gaius is not himself, so to speak.
** Similar to the ''Series/{{Angel}}'' episode with Fred and Gunn, when Arthur breaks up with Guenevere in season 4 on the advice of Agravaine, Gwen immediately asks if someone talked him into it and she doesn't buy for a second that he made the choice on his own.
* ''Series/MissFishersMurderMysteries'': In "Death at the Grand", Aunt Prudence is held hostage and forced to call Phryne to lure her into a trap. Aunt Prudence says that she has decided to stay for lunch because Mr Butler is making shepherd's pie and Phryne knows how much she loves it. Phryne immediately realises something is wrong as Aunt Prudence hates shepherd's pie.
* In an episode of ''Series/{{Monk}}'', Adrian realizes that a man who claims to be the brother of a missing person isn't really his brother, since they used different terms for soft drinks (pop vs. soda).
* In the ''Series/MyBabysittersAVampire'' episode "Guys And Dolls", Jane brings her favourite doll, Debbie Dazzle (a parody of [[Music/Katy Perry Katy Perry]], to life with Benny's spellbook. Ethan then dresses up as Debbie Dazzle's male counterpart, Dazzle Dan (a parody of Barbie and Ken), to distract her so that Jane can turn her back into a doll. Unfortunately, he accidentally gives himself away when he asks her to take a ride on his speedboat, which Dazzle Dan doesn't have.
* ''Series/{{NCIS}}'':
** "Bête Noire".
*** Kate attempts this when she brings a box of evidence down to the autopsy room on Abby's request only to find that Ducky has locked down the room and won't let anyone in. She pretends to be Abby, providing Ducky with the opportunity to confirm that something is amiss by playing along. Unfortunately the terrorist holding Ducky hostage realizes what they're doing, and Kate ends up a hostage as well.
*** Also in the episode when Ducky orders Abby to bring him the evidence ending with "stat!" "Stat!" is medical slang for needing something quickly but only used in hospitals with living patients. It isn't something a coroner should use. Realizing this alerts Gibbs that there is trouble and a possible hostage situation in autopsy.
** In the episode "Bait", Gibbs is being held hostage by a teenager wearing a suicide bomber vest and demanding to see his mother. When the team finds out that the boy's mother is considered dead, Tony tells Gibbs that "Special Agent Caitlin Todd" is looking for her. When one of the local LEO's asks why Tony didn't reveal the mother's death, he says he already has. [[spoiler:Special Agent Caitlin Todd is dead.]]
** In "Detour", the two characters in danger even do this inadvertently. When Gibbs notices that Jimmy and Ducky haven't returned from the crime scene (they've been abducted by people seeking something from the murder victim), he asks Abby to call them. Gibbs realizes something is seriously wrong when Abby fails to reach them, noting that it's odd that Ducky's phone has been turned off as he never does that and that Jimmy has removed the battery from his, asking, "Why would he do that?". Gibbs responds that "He ''wouldn't''", and the next shot is of the team frantically scrambling to find them.
* ''Series/NCISNewOrleans'':
** In "The Insider", Loretta is being held hostage by a gunman. When Pride asks her about the victim on her slab, she says that he died from "Larrabee's syndrome". Pride recognises this as a QuietCryForHelp because Captain Larrabee was an officer who was killed working a hostage situation with Pride years before.
** She also attempts this with a security guard who tries to stop her and the man from leaving by cheerfully declaring "Everything's fine, Darryl". Unfortunately, the guard's "Huh?" reaction, plus the guy getting glimpse of his name tag, which reads "Lowell", tips him to what she's trying to do.
** Percy alerts [=LaSalle=] to the fact that she's in danger by declaring "Everything's fine, City Mouse". Aside from the fact that they'd just decided to retire their pet names for each other, that's HIS nickname for HER.
* ''Series/OneLifeToLive'':
** When Rebecca is kidnapped by escaped rapist Todd, she manages to tip her friends off to where she's being held (he lets her make one phone call to assure them that she's all right) by referring to a Bible verse that they had been discussing shortly before she was abducted.
** Andy and Antonio have gone to New York for a romantic weekend, unaware that they are being stalked by a hitman who's pretended to befriend them. When Andy figures out what's going on, she quickly reminds Antonio that he needs to call his sister so that they can have an excuse to get away without arousing the hitman's suspicions. Antonio doesn't have a sister. Unfortunately, his brief moment of confusion before he realizes what Andy's trying to do tips the gunman off to the fact that they're on to him.
** When Todd terrorized a blind Nora at the beach house where she and Bo were spending Christmas, Bo showed up. Todd ordered her to get rid of him while he hid. Nora did so, but told Bo not to "''Film/WaitUntilDark''" to return. After driving away, Bo suddenly remembered that he and Nora had been discussing the movie shortly before he left the house to run errands, and recalled the plot -- a blind woman being terrorized by an assailant. At that, Bo realized that Nora had been trying to tell him that Todd was there in the house.
* ''Franchise/PowerRangers'':
** ''Series/MightyMorphinPowerRangers'':
*** In the episode "The Wannabe Ranger", Jason is able to see through the Primator's impersonation of Tommy when the monster suggests they give up, something the real Tommy would never say.
*** The Primator screws up ''again'' when impersonating Trini. The Rangers have trouble distinguishing between the real one and the fake at first, so Jason suggests that both of them ''fight'' him, so he'd be able to tell by both of their styles who's real and who's not. But as Jason was counting on, the ''real'' tip-off is that the real Trini refuses to fight him at ''all'' because he's her friend, while Primator disguised as Trini enthusiastically jumps at Jason with daggers poised to strike. Jason promptly orders the other rangers to shoot Primator down.
** During ''Series/PowerRangersInSpace'' the villain Astronema uses a monster's disguise ability to disguise herself as the Yellow Ranger, during the episode, the real Yellow Ranger returns to help the team, but loses her Morpher, which the Red Ranger retrieves and then the Red Ranger has to figure out which one is the real one, how does he do so, only the Rangers would know how to activate the Morphers, thus, he asked them both, and Astronema didn't know.
* ''Series/{{Psych}}'':
** Lassiter gets a text message from "Shawn" and follows it right into the trap the killer set. When Lassiter gets there, a captive [[ManChild Shawn]] says, "I can't believe you thought that text was actually from me. It lacked all nuance, was lacking my signature mocking tone, and was totally devoid of emoticons."
** In a later episode, Shawn has been kidnapped. He calls Juliet, ostensibly to tell her that he believes he's going to die and wanted to talk to her one last time. He ends the call by saying, "Goodbye, Abigail," cluing her in to the fact that there was a hidden message in what he said. She can't figure it out, but she repeats the conversation to Shawn's father, who does.
** Still later, Shawn is in the hospital and being held at gunpoint while FaceTime-ing with Gus, Juliet, and Lassiter. Shawn gives them a false lead at the insistence of the bad guy. Gus realizes that something is up since Shawn didn't make any obscure analogies or use over-the-top theatrics as he normally does.
* ''Series/QuantumLeap'':
** About OnceAnEpisode, Sam's mannerisms will leak through, or a conversation with Al will be overheard, causing the people who know the leapee to do a double take. However, no one suspects anything, and Sam gets pretty good at playing it off.
** The episode "The Boogieman" has numerous in regards to Al: He's dressed in a conservative suit, his handlink never lights up nor does he ever really use it, he's never seen walking through any objects, and he never opens the Imaging Chamber door. It's finally revealed in the final act that [[spoiler: he's been Satan in disguise.]]
** It does come back to bite Sam in "Return of the Evil Leaper", when evil hologram Zoey notices "Arnold Watkins" talking to thin air, including an utterance of the name "Al". A quick scan by Lothos confirms that Sam is indeed there.
* ''Series/RedDwarf'':
** In the episode "Psirens", the crew is trying to figure out which of two Listers is a mind-reading impostor. The two act alike, until the crew has one of them play Lister's guitar. Because Lister sincerely (but utterly incorrectly) considers himself a brilliant player, the fake reads this, belts out a few power-chords, and goes down in a hail of laser-fire.
** Played straight earlier when Dave realizes that the "Kryten" that saved him was not really Kryten, since Kryten never calls Lister "Dave".
** In series one, Rimmer once tried to trick Lister out of taking a test that would have made him Rimmer's superior, and allowed him to replace Rimmer with a hologram of his crush Kochanski. He does this by taking on Kochanski's appearance, and telling Lister that she would never be interested in him. However, his performance is pretty lousy; "Kochanski" repeats some phrases Rimmer often uses, is easily bluffed when Lister mentions a fake tryst they had, and then tries to cover up her weird behavior by saying she's "having a woman's period".
* ''Series/{{Rescue 911}}'':
** In a chilling episode, a woman is told by a rapist to call in sick to her workplace. She promptly dials a male friend and tells him, "I can't come in to work today," thus alerting the friend that she's in trouble and he needs to stop by PRONTO. A few seconds later, she does the same thing again with 911, and the dispatcher immediately works out that there's something wrong and sends the police.
** There was a similar episode of ''Series/ISurvived''. When a woman's crazed ex-husband broke into her house and threatened her, she managed to stall him by telling him that her friend was coming to take her shopping and that she needed to cancel her plans. Amazingly, he let her call. When the friend answered, the woman proceeded to cheerfully tell her that she couldn't make it and not to bother coming. Initially confused--because they did NOT have plans to get together--the friend quickly realized that something was wrong and asked if the woman's husband was there. Upon being told "yes", the friend immediately called 911.
* ''Series/{{Scorpion}}'': In "Shorthanded", Toby tells the rest of the team they can pick him up at a location in the desert directly under the belt of Orion. He does this to tip them off that they are walking into an ambush, as they will know that that constellation was not visible in that hemisphere at that time of year.
* In ''Series/{{Sherlock}}'', John is kidnapped and forced to fool Sherlock into thinking he's Moriarty. There are many, many indications that something is obviously not right, such as John blinking SOS at Sherlock, speaking in an unusual monotone, and wearing a thick jacket (with a bomb-strapped vest underneath) that he was a) not wearing when he left Baker Street and b) according to Mrs. Hudson, would never wear anyway. There is no indication that Sherlock picks up on any of these hints, which is a pretty big Out Of Character Alert in its own right, showing how deeply shaken he is at the prospect of John's friendship being a lie.
* ''Series/{{Smallville}}'':
** When Clark's on red kryptonite, he always refers to himself as "[[SuperpoweredEvilSide Kal]]". Although his offensive and sexually aggressive attitude should tip you off quick.
** "[[IronicEcho Clark Kent]] [[ThatManIsDead is dead.]]"
** [[FreakyFridayFlip Lionel in Clark's body]] has cruel comments for both Lana and Chloe, but the most obvious alert comes when he referred to Chloe as "Miss Sullivan".
* ''Series/StargateSG1'':
** A variant is used in an episode where Daniel, trapped behind enemy lines, is relaying a battle plan to the SGC via radio through what sounds like small talk, mixing in Goa'uld words to let them know what his plan is. If the message was translated, it would sound something like, "Oh, and could you have Teal'c water my ''coordinated pincer attack''?"
** A straighter example would be when O'Neill and Teal'c are stuck in a time loop, but everyone else's memories are reset. O'Neill tries to prove it by explaining why the planet they're visiting is important before Carter has a chance to. Later, Carter and Hammond have the following conversation:
--->'''Carter:''' Besides, when was the last time you heard the colonel use words like "geomagnetic"?\\
'''Hammond:''' You have a point there.\\
'''Carter:''' And he was using them ''correctly''. More or less.
** Also from that episode:
--->'''O'Neill:''' Now, how did I know you were going to say that?\\
'''Carter:''' Maybe you read my report?\\
'''Daniel:''' (''skeptically'') Maybe he ''read'' your ''report''? (''raises eyebrows'')
* ''Series/StarTrekDeepSpaceNine'':
** In "Heart of Stone", Odo spends a lot of time with Changeling!Major Kira. He only realizes it is a double when "she" says "I love you".
** Subverted in "Armageddon Game": an alien government has faked the deaths of O'Brien and Bashir (while trying to hunt down and actually kill them) in an attempt to destroy all knowledge of a dangerous bio-weapon. They send a recording of a faked lab accident to Deep Space Nine, using security footage from earlier on. But O'Brien's wife notices him drinking coffee, which he would NEVER do in the afternoon, and her suspicions along with the shady explanation of the accident itself is enough to get Sisko and the others to investigate further. At the end of the episode, O'Brien is recovering at home and asks for a cup of coffee after lunch, explaining to his shocked wife that sure, he drinks coffee in the afternoon sometimes...
* ''Series/StarTrekTheOriginalSeries'':
** In the episode "What Are Little Girls Made Of". A robotic double is made of Kirk, with the robot having a duplicate of his mind as well. Kirk foils the plan during the procedure by mentally focusing on a racist insult toward Spock, something he would never normally say but which is consequently implanted into the double.
** There's another one in "Whom the Gods Destroy," when the villain tries to bluff his way out of failing a TrustPassword test by telling Scotty that he was just testing to make sure that he wouldn't let anyone beam up without the password. Given how long Kirk and Scotty have known one another, and how much they trust one another, Scotty immediately figures out that the "just testing you" story is bogus.
** Before them was "The Enemy Within". Kirk is split into his good and evil sides by a transporter accident, which leaves several of the ''Enterprise'' crew stranded on a hostile planet. Spock feels a bad vibe when the evil Kirk, passing himself as the good one, walks onto the bridge. Then he declares that the men can't be saved and orders the ship to leave orbit, at which point Spock ''knows'' it's not the real one -- since when would [[AFatherToHisMen James T. Kirk]] leave his crew to die?
** In "Turnabout Intruder" (essentially ''Star Trek'' meets ''Film/FreakyFriday''), numerous things, actually. First, "Kirk" hits "Lester" hard enough to knock her down. Then he disintegrates into screaming hysterically at Spock and accusing him of mutiny. When he orders the "traitors" executed, it completely cements the suspicion in every officer's mind. Sulu and Chekov flat out refuse to follow his orders after a while. Scotty even tells [=McCoy=] while trying to convince him to side with Spock that he has seen Captain Kirk in all sorts of moods, but never "red-faced with hysteria".
** And of course, "[[Recap/StarTrekS2E4MirrorMirror Mirror Mirror]]". Neither Kirk can keep up the charade of being the other for long. Fortunately, they're both dealing with Spock.
---> '''Spock:''' It was far easier for you as civilized men to behave like barbarians, than it was for them as barbarians to behave like civilized men.
* ''Series/StarTrekTheNextGeneration'':
** In the episode "Allegiance", Picard is replaced by a double who has his memories but doesn't act like him very well--basically doing the kinds of things Picard would do if he weren't an incredibly reserved man (one of the weird things the doppelganger Picard does is go into [[GoodGuyBar Ten Forward]], order drinks all around, and start singing). When the real Picard asks Riker what the giveaway was, he is told: "Well, sir, I find it hard to believe that [[TakeThat you're that good a singer]]." The aliens who abducted Picard reveal that this was really part of their experiment to study the concept of hierarchy, which was alien to them because they were a HiveMind. In Picard's case they wanted to test how far the crew's respect for the Captain's authority would go with his increasingly erratic behavior. The bridge crew draw the line only when the duplicate gives a suicidal order for no reason.
** In "The Most Toys", Kivas Fajo almost perfectly faked Data's death. He messed up in one key area, though; Data's final transmission, fabricated by him, was phrased incorrectly. The crew had been ferrying materials between their two ships, and Data had robotically repeated the exact same status report each time. The last one was missing the notification that he was launching the shuttle--Data had been incapacitated before the shuttle launch.
** In "Datalore", an android physically identical to Data named Lore incapacitates Data and impersonates him, but slips up in subtle ways. He gives himself away to Wesley by using a contraction, something that Data never does.
** "The Schizoid Man" has another Data impersonator, a dying scientist named Ira Graves who uploads his consciousness into Data. Graves is egotistical and contemptuous of authority, and the Enterprise crew knows something is wrong almost immediately when "Data" starts displaying those qualities, but just not exactly what. He tells Picard he's "as strong as a Regellian ox", which Picard doesn't pick up on because he wasn't there when Graves said it earlier, but looking back, he realizes pretty much ''everything'' Graves said should have been a dead giveaway.
** In "Future Imperfect", Riker figures out he's trapped in a simulation, and asks the crew questions they can't answer so that whoever is running the simulation will stop trying to fool him. Geordi can't justify running a level 1 diagnostic for over a day, which is in fact a HandWave for the simulation's imperfections; Worf can't recall where he got a scar; Data can't make anywhere near trillions of calculations per second, and, like Lore, uses contractions.
* ''Series/{{Supernatural}}'':
** In ''Hunted'' when Gordon uses Dean as bait and forces him to call Sam, Sam instantly knows that something's wrong because Dean used the codeword "Funkytown". [[spoiler:Subverted: Gordon knew that Dean would find a way to alert Sam and was leading him into a trap]].
** Done several other times. Once by a shape-shifter. Another time the body of another supernatural hunter was possessed by the SevenDeadlySins. In "The Great Escapist", Kevin Tran realizes that two people who look and sound just like Sam and Dean are impersonators because they are being too patient and helpful. The irony that a pair of demons would be too nice to convincingly pass as the heroes does not go unnoticed.
** A plot point in season six, when [[NiceGuy Sam]] has been behaving [[JerkAss a little]] [[TheUnfettered out of character]]. Turns out [[SoullessShell his body had no soul in it]]. Played with because it took Dean a third of a season to notice, so this trope was invoked for viewers as much as characters. What caused Dean to realize something was up was Sam letting Dean get turned into a vampire, as Dean saw that Sam didn't seem bothered by it and was actually smiling rather than trying to save him.
** An early and depressing example is the end of the first season when they realize their father is possessed by a demon because he tells them he's proud of them, while they believe the real John would just have been angry that they'd "wasted" a very limited resource.
* ''Franchise/SuperSentai'':
** DoubleSubverted in ''Series/HyakujuuSentaiGaoranger''. When the MonsterOfTheWeek disguises himself as White, both Whites (who conveniently wear different clothes thanks to the event that happened earlier) ask Red to hand her TransformationTrinket. He holds it out to [[EvilWearsBlack the one dressed in black]], who walks up to him, treading on a flower along the way. The one who accidentally treads on a flower is the impostor? No, they both do. The one who does not feel sorry for the flower is the impostor.
** In an episode of ''Series/KaizokuSentaiGokaiger'', the MonsterOfTheWeek assumes the form of Yellow Ranger Luka. Near the end of the episode the rest of the team reveals that they were aware for some time, since at dinner the monster ate broccoli, a food Luka absolutely despises.
* An episode of ''Series/TalesFromTheCrypt'' had the bad guy threatening the protagonist with his wife's gun, which she normally keeps in her purse for self defence. With the husband taken hostage using the gun, he attempts to lure the wife in by telling her that the husband is threatening to commit suicide with the same gun he's holding. Unfortunately for the bad guy, both husband and wife know that [[spoiler: the wife [[ItWorksBetterWithBullets doesn't keep any bullets]] in the gun.]]
* In one episode of ''Series/TeenWolf'', Stiles, Scott and Allison [[ItMakesSenseInContext have to kidnap Jackson]]. To throw off suspicion, Stiles sends a text from Jackson's phone to his father that says: "Stayed at friend's house last night. Everything fine. Love you." Jackson's father immediately knows that something is wrong, because Jackson hasn't been able to tell his parents that he loves them since they told him he was adopted, eleven years ago.
* Inverted on ''Series/WithoutATrace''. An abducted woman is forced to call her husband and assure him that she's fine and that's she's merely hanging out with an old friend, rather than being kept there by force. Not believing her claims of being all right, her worried husband tells her to ask about their children if she's in fact being held prisoner. When she manages to cheerfully ask how the kids are, he realizes she's in trouble.
* On ''Series/TheXFiles'', this happens with a twist. In the episode "Small Potatoes", Mulder is kidnapped by a shape-shifter who decides to steal Mulder's identity... literally. In "Dreamland", Mulder and an MIB switch bodies. Both non-Mulders try their hand at seducing Scully. The MIB was so sleazy about it that some of the things he said were a big sign to Scully that Mulder was NotHimself. Plus, they both called her "Dana", which Mulder ''never'' does unless things are really bad.
* ''Series/BlakesSeven''. In "Shadow", Blake tries to purchase the help of [[TheSyndicate Terra Nostra]] only to be captured instead. They force him to call Cally on the Liberator, so Blake tells her to send Zen across in the shuttle with the money (Zen is actually their MasterComputer and built into the spaceship). However this backfires because his captor assumes Blake came there by shuttle (he was teleported, but that's not a well-known technology) and therefore that's a CovertDistressCode -- his shuttle should still be on the SpaceStation, not the Liberator. Blake has to bluff him into believing the Liberator has [[StarshipLuxurious more than one shuttle]]. It should be noted that the crew of the Liberator never do establish a CovertDistressCode, despite several occasions where they're coerced (or their voice is faked) to get someone to teleport up a BoardingParty.
* ''Series/TheGreatBritishBakeOff'': The contestants can act considerably different when the stress gets to them.
** Constantly chill Selasi often admits he's making it up as he goes along, plays with his ingredients and spends a lot of time joking with fellow competitors. In the series 7 semi-final he paces around frowning and actually admits he's worried.
** Engineer Andrew was famously exact in his baking, often drawing stencils and to-scale diagrams of his cakes, and even making an excel spreadsheet timetable for the series 7 finale. When he fills his Victoria Sandwich blind in the finale and mutters "screw measurements", it's clear that he's short on time.

[[folder:Video Games]]
* ''VideoGame/SuperRobotWars'':
** Original Generation'' subverts this. When a main character's girlfriend disappears and later reappears, the character remarks that it's not her, because "even she wouldn't be silly at a time like this". When they break the mind control, she acts just like she did when she was mind-controlled. Another character mutters "Would never act like this in this situation, huh?".
** During the attack on the Omega Missile base in ''VideoGame/SuperRobotWarsCompact3'', Folka then attacks Fernando and demands to know what is wrong with Fernando since Fernando isn't usually this kill happy but Fernando says what's wrong with that, all Shura are born to fight and kill and strive for the position of General. Folka wonders what changed Fernando like this but Fernando tells him to shut up and fight and die. After beating him, Fernando then says, "What a redundant moron" which perks Folka's ear and Folka says that he won't be hesitant anymore, he'll defeat Fernando and Fernando says that Folka can try. Folka then smirks and says "How about revealing your true face... You can't fool my eyes." "Fernando" then asks how Folka knew that he wasn't really Fernando and Folka says that he hasn't forgotten Fernando's fist (The way of the martial arts, fighter recognize, communicate, etc with their fist) "Fernando" reveals himself to be Arco who says that he didn't think Folka had gotten this strong and Folka says that the power of belief has made him stronger. Arco then says that when the REAL Fernando awakens then Folka wouldn't be talking big like this and Arco notes that this is it for him, looks like what that girl said was true.
* In ''VideoGame/TeamFortress2,'' while the Spy's disguise looks and sounds perfectly like whomever he's disguised as, there are many ways a seasoned player can detect a Spy by just looking at their behavior. For example, a Spy disguised as a Scout appears to move unnaturally slowly, since he's the only class that moves faster than 107% of base speed, the upper limit of how fast the Spy can move.
** Another sign is if a Medic isn't healing people obsessively to build his Ubercharge up: if a Medic is walking around with his syringe gun out, you may be dealing with either an amateur Spy or a [[CombatMedic Battle Medic.]]
** There are also some voice lines that are wired to only play if you're on the attacking/defending team: if you're defending, and someone on your team says something along the lines of needing to push the bomb when the cart is rolling back, he's definitely a Spy.
** There is no way for the Pyro to be set on fire due to his flame-retardant suit. Thus, if a burning Pyro is running amok, he is certainly a Spy.
* In ''VideoGame/MarvelUltimateAlliance'', Doctor Doom's henchmen get "Dum Dum" Dugan to come to the S.H.I.E.L.D. Omega Base by relaying a DistressCall. However, ComicBook/NickFury figures out it is a trap when Dugan (purposefully) lists Bruce Banner as being a scientist researching the Super Soldier Serum when he is in fact assigned to the Gamma Bomb project.
* In ''VideoGame/StarControl II'', when you meet the final remaining Shofixti warrior, his sensors are nonfunctional and he assumes that you are an Ur-Quan destroyer sent to hunt him down. The only way to convince him that you are friendly, counterintuitively, is to insult him repeatedly. The Ur-Quan, for all their faults, are always very polite, even when preparing to kill an enemy. Eventually he realizes this and accepts that you are not an Ur-Quan.
* In ''VideoGame/TheKingOfFighters'', for all of her massive flaws Rose Berstein loves her older brother Adel and always tells him what's on her mind. When Adel finds out that she has [[spoiler: become the new host for the KOF tournament ''and'' has built a whole new and lavish stadium for it]] ''behind his back'', he's extremely disturbed and thinks something's ''very'' wrong. [[spoiler: He's right: Rose has been {{brainwashed}} by Those of the Past and is their UnwittingPawn. ]]
* The last mission of the second week in ''VideoGame/TheWorldEndsWithYou'' is ever-so-slightly inconsistent with the missions issued earlier in the week, as this one did not have any math-related puns in the message. Neku and Joshua notice this, but as it's still an official mission and the alternative is [[DeaderThanDead being erased]], they do it anyway. [[spoiler: Turns out it wasn't issued by the Game Master, but by the Conductor, who had decided the GM had gone rogue and needed to be eliminated.]]
* One comes up in [[VideoGame/TalesOfSymphonia Tales of Symphonia's]] sequel, Dawn of the New World; when Emil, Marta and Zelos come across two Lloyd Irvings fighting, both Lloyds urge them to believe they are the real Lloyd and to strike down the other. The player is given the choice to decide who is the real Lloyd after hearing each one give their speech. The fake is the Lloyd who declared the fight was for [[spoiler:justice]], which is something the real Lloyd has vehemently said in the original ''VideoGame/TalesOfSymphonia'' was a word he hated.
* ''VisualNovel/FleuretBlanc'' provides an example of someone else setting up a person as out-of-character rather than acting out-of-character themselves: [[spoiler:Junior]] tries to deflect blame for the anonymous text messages by pinning it on [[spoiler:Le Neuvieme]] -- but [[spoiler:the messages are in English, and Le Neuvieme only speaks French]]. [[RevealingCoverup This allows you to figure out the real culprit]].
* In a tidbit of Irelia's backstory in ''VideoGame/LeagueOfLegends'', it's revealed that her test to become a champion involved a simulated battle with her father, a legendary swordsman known for feats such as staying dry on a rooftop during a rainstorm. Despite being terribly outmatched, she quickly realizes the deception when her brother swings in from the side and manages to land a blow, and promptly impales the illusion with her blade.
* In ''VideoGame/CastlevaniaSymphonyOfTheNight'', Alucard comes across a scene of his human mother. He quickly becomes emotional and promises to save her. Then his mother starts saying hateful things against human beings, something his real mother would never say. Then it's revealed that the whole thing was an illusion set up by a powerful Succubus. [[BerserkButton Alucard isn't]] [[CurbStompBattle pleased]].
* Subverted in ''VideoGame/FireEmblemFates''. In the ''Birthright'' and ''Revelation'' paths, the party stops in the country of Izumo, and are greeted by its leader, Lord Izana. Izana acts like a cross between a party animal and a rich kid, which Hinoka takes as a sign that he's an imposter. And indeed, he was replaced by the Nohrian mage and MasterOfIllusion Zola. But when the real Izana is freed, ''[[BunnyEarsLawyer that's exactly how he acts]].''
-->'''Sakura:''' I-Is this still Zola?
-->'''Hinoka:''' No, but I think we may have underestimated Zola's impersonation.
* ''VisualNovel/PhoenixWrightAceAttorneyTrialsAndTribulations'':
** Phoenix ''thinks'' this trope is in play in the first case when Dahlia starts acting all-around bitchy. After Mia revealed Dahlia to be a major BitchInSheepsClothing, who only dated Phoenix to get certain necklace and tried to kill him, when seduction failed, she didn't feel need to pretend anymore. Phoenix however still [[LoveMakesYouDumb crazy in love with "Dollie"]] claims after the trial, that this Dahlia was a fake. [[spoiler:In a way he's right. The girl he ''actually'' dated at the time was Dahlia's twin sister Iris, who really was a NiceGirl.]]
** [[spoiler:When [[YamatoNadeshiko Iris]] starts acting like ExtremeDoormat and makes some InnocentlyInsensitive comments it's a clue that [[EvilTwin Dahlia]] is impersonating her.]] Phoenix ''does'' notice that something's off, but since he met said person just two days earlier [[spoiler:(or rather he thinks he did)]] he doesn't connect the dots immediately.
* In ''VideoGame/EmperorRiseOfTheMiddleKingdom'', spies disguise themselves as regular citizens but don't follow the walking pattern of that citizen type, making them easy to catch when they bypass roadblocks or show up in the wrong city district -- assuming they don't just skip their research and [[PaperThinDisguise dress as a worker from an industry your city doesn't have]].

[[folder:Web Comics]]
* A ''Webcomic/{{Nodwick}}'' strip details a dungeon crawl where the group finds a high-up switch. The group is tipped off that something is amiss (viz. he's been replaced by a doppelganger) when Yeagar, looking for something to throw at it, [[http://comic.nodwick.com/?comic=2002-05-02 ignores Nodwick in favor of a rock lying at his feet]].
* In ''Webcomic/QuestionableContent'', Faye and her CrazyPrepared mother have worked out a code phrase for when Faye was being held against her will.
--> '''Faye''': No mother, the peaches are '''definitely not ripe'''.
* ''Webcomic/TheOrderOfTheStick'':
** Belkar... uh... subverts? ([[ZigZaggingTrope double-subverts? parodies?]]) this during the aftermath of a fight with the thieves guild. Celia and Hayley interpret it as Belkar gone... well, more insane than usual, since "usual" means "kill everything not allied to me."
--->'''Belkar''': Let's stop the violence.
--->'''Side Character''': See? Even your other party member agrees which means-
--->'''Celia and Haley''': (together) [[OhCrap RUN FOR YOUR LIVES!]]
** [[http://www.giantitp.com/comics/oots0723.html Later]], Tarquin figures out that Elan is not [[EvilTwin Nale]] partly because Elan [[http://www.giantitp.com/comics/oots0722.html surrendered]] to save a teammate, which [[ItsAllAboutMe Nale]] would never do.
--->'''Tarquin''': Plus, he didn't rant about his [[SmugSnake intellectual superiority]] even ONCE.
--->'''Malack''': Now that you mention it, I did find that odd.
** During [[DivorceIsTemporary their parents' remarriage]], [[http://www.giantitp.com/comics/oots0889.html Elan tells Nale not to object or cause trouble, which Nale calmly agrees to.]] This is the first step to make Elan realize [[spoiler:he's in a LotusEaterMachine]].
--->'''Nale:''' Did you ever think that maybe I'm tired of fighting, and that I just want to enjoy one day with my family?
--->'''Elan:''' No, that--that's not how you would react to this. That's how I would ''want'' you to react. At the very least, you should be trying to kill me for being chosen Best Man over you!
** Later in the story, when the [[spoiler: High Priest of Hel]] casts Control Weather, Belkar seizes on this as proof that [[spoiler: he is not Durkon, as Durkon wouldn't need to prepare the spell, much less use it to stop a storm. He could simply pray to Thor, Durkon's patron.]] Unfortunately, [[CassandraTruth no one believes him.]]
** [[spoiler:The High Priest of Hel finally makes a serious error in trying to do a BreakingSpeech on Roy by bringing up his inability to save his baby brother. That makes Roy realize this creature is in no way Durkon at all.]]
* Played with in ''Webcomic/TerrorIsland''. In [[http://terrorisland.net/strips/184.html this strip]], the protagonists recognize that their friend Jame is possessed by a demon, when he says "SOUNDS LIKE SOMEBODY HAS BEEN EATING SOUR GRAPES." But when the demon is banished from Jame, [[http://www.terrorisland.net/strips/185.html he says exactly the same thing]], and Sid proclaims "That's our Jame!" Unless it's because demons simply [[PaintingTheMedium talk with different]] SpeechBubbles...
* ''Webcomic/GirlGenius'':
** In Othar Trygvassen's('''''GentlemanAdventurer''''') [[CharacterBlog twitter]]:
--->"That letter is a fraud! Othar Tryggvassen may do things that lesser men find objectionable or slightly illegal, but I never apologize!"
** In the comic, how does Dimo know that someone besides the Jager generals is present when he goes to report in to them? [[http://www.girlgeniusonline.com/comic.php?date=20110314 "... schmelled soap."]]
* In ''Webcomic/SomethingPositive,'' Eva had an Internet romance with someone who claimed to be Davan. Davan's friend Josh, however, was suspicious, partially because the e-mails all had perfect spelling, something Davan apparently doesn't bother with. Unfortunately for Eva, she didn't listen.
* In ''Webcomic/{{Exiern}}'' Neils tries to drop hints [[http://www.exiern.com/?p=1340 here]] that he has been be-spelled and is no longer fully in control of his own actions by calling Crown Princess Peonie the "Second In Line To The Throne" instead of the first. It seems like no one notices at the time though. Peonie had to have it spelled out to her after the inevitable kidnapping, but her father was just going along with it 'til he could get his other assets in play.

[[folder:Web Original]]
* In the Literature/WhateleyUniverse story "Test Tube Babies", team superboy Lancer is fighting a power mimic/shapeshifter who now looks like Lancer. One of them yells at a teammate with an anti-brick weapon to 'shoot both of us'. The teammate blasts that one senseless. Not only is the teammate savvy, but they have communicators they would really use instead.
* One episode of ''WebVideo/AtopTheFourthWall'' has 90s Kid suggesting a Nirvana reunion that involves digging up Kurt Cobain's body and having zombie chicks play him like a puppet. It isn't until later, but it finally dawns on Linkara that not even 90s Kid is that twisted, leading him to realize [[spoiler: he's been possessed by The Entity]]
* In ''WebVideo/ToBoldlyFlee,'' WebVideo/TheNostalgiaChick and [[WebVideo/BrowsHeldHigh Oancitizen]] infiltrate [[KneelBeforeZod Zod]]'s ship disguised as his old friends, [[DoctorGirlfriend Ursa]] and [[TheBrute Non]]. Unfortunately, Non is mute, and Oancitizen can't resist talking. And he ''really'' can't resist [[http://www.youtube.com/watch?v=JQeSpRyxrDY singing]]...
* In ''Literature/{{Worm}}'', one of these acts as a WhamLine in [[spoiler:[[http://parahumans.wordpress.com/2012/09/29/prey-14-8/ Chapter 14.8]]]], when [[spoiler:Bonesaw]] is pretending to be [[spoiler:Tattletale]] in order to gain Skitter's trust.
* During the first episode of the Yellow Temperance mini-arc in ''WebVideo/VaguelyRecallingJoJo'', Jotaro realizes that Kakyoin is a fake after witnessing Kakyoin in the act of devouring some beetles. Jotaro punches the fake Kakyoin in the face, which gets him to reveal himself as Rubber Soul. This is pretty much what happened in the arc it's parodying, oddly enough. It helped that Rubber Soul is a jackass who doesn't bother trying to mimic his target; he ''likes'' making them look like sudden assholes.

[[folder:Western Animation]]
* Subverted in ''WesternAnimation/AmericanDad''. Francine is threatening Stan with a gun for trying to ditch her at her high school reunion with his CIA body double, Bill. One of them gives a heartfelt speech about how he was selfishly putting her down while trying to make up for his past inadequacies. Francine determines that the real Stan would never say something so sincere and shoots the opposite [[spoiler:who, [[AccentRelapse reverting to his Southern accent]], turns out to be Bill the double, after all. Stan [[JerkWithAHeartOfGold really was apologizing]]]].
* In ''WesternAnimation/AquaTeenHungerForce'' a (very degraded) clone of Shake was caught when Frylock suggested they give blood.
-->'''Frylock:''' The real Master Shake thinks the blood drive is a pyramid scheme. Perpetrated by Dracula and his night slaves.
* The best way to free someone of Purple Man's control in ''WesternAnimation/TheAvengersEarthsMightiestHeroes'' is to point out to the victim that they themselves are doing or saying something they would never do. Cap is freed by pointing out that he doesn't believe in forcing things on others; Hawkeye is freed by pointing out that Hawkeye never blindly obeys anyone, not even his superiors; Ms. Marvel is freed when it's pointed out that she'd never carelessly ignore her allies in distress, etc.
* ''WesternAnimation/BatmanTheAnimatedSeries'':
** In an episode, the daughter of the mechanic who works on the Batmobile is kidnapped. With the bad guys listening in, Batman asks where she is, and the mechanic responds that she's "in the basement", which is apparently racetrack slang for in big trouble.
** In "Mudslide", a young security guard caught what he thought was a thief stealing his boss' safe, until he saw his boss telling him to get back to his post. The guard was about to leave when he noticed his boss's accent is gone and remembered he was on vacation in Hawaii. The "boss" knocked him out by throwing clay at him.
** In [[http://dcanimated.wikia.com/wiki/Knight_Time Knight Time]], [[WesternAnimation/SupermanTheAnimatedSeries Superman]] arrives in Gotham, as Batman has gone missing. During the investigation, Robin shows a video message of Bruce Wayne calling Lucius Fox about going away for a while. When Supes asks what's wrong with it, Robin points out that Bruce chuckles at the end. Bruce Wayne ''never'' smiles, much less laughs. Turns out he's under Brainiac's mind control, but not because he's Batman (which Brainiac doesn't know) but because he needs access to Wayne Enterprises resources.
* In an episode of ''WesternAnimation/BatmanBeyond'', Bruce realizes that his "inner voice" isn't really his, that he's under suggestion by the villain Shriek:
-->'''Bruce''': The voice kept calling me "Bruce". In my mind, that's not what I call myself.\\
'''Terry''': What do you call yourself? ''[Bruce gives him a pointed look]'' Oh, yeah. I suppose you would. ''(in Batman voice)'' But that's my name now.\\
'''Bruce''': Tell that to my subconscious.
* In the ''WesternAnimation/{{Ben 10}}'' episode "Perfect Day", Ben is trapped in a {{Lotus Eater Machine}} by the Forever Knights where he is seen having "the best day ever". He then encounters a dream version of Vilgax who is ''completely'' out of character, as he only tried to send Ben to the Null Void and wasn't even after the Omnitrix. Ben didn't notice this until it was pointed out by the real Gwen (who,along Grampa Max, entered the dream world to rescue Ben using special helmets from the Rust Bucket).
* ''WesternAnimation/CodeLyoko'':
** XANA traps the team (except Jeremy) in a virtual version of the real world. Jeremy enters Lyoko to rescue his friends, and is confronted by an evil, virtual version of himself. Each tries to convince Odd, Ulrich, and Yumi that they are the real one. Evil Jeremy gives himself away when he says he would "never go into Lyoko", but they know that the real Jeremy WOULD go into Lyoko if it meant rescuing his friends.
** XANA sends a polymorph clone to manipulate the Lyoko-Warriors by using their feelings against each other. At one point, the clone, while impersonating Jeremy, kisses Aelita to prove he is the real Jeremy, which ironically fails since she knew the real Jeremy was too shy to ever dare do it. Later in the same episode, Odd is facing the real Yumi and the clone in Yumi's form at the same time, and actually recognizes which one is real when the real Yumi insults him, because "XANA respects him too much to insult him."
** XANA is pretending to be Franz Hopper. He gives himself away when he calls the Skidbladnir an odd name for a ship, when the real Franz Hopper was well versed in Norse Mythology.
* ''WesternAnimation/CodenameKidsNextDoor'':
** There's a parody that then switches to being played straight. In the P.O.O.L episode, all of Numbuh Four's friends get replaced by doubles from a negative universe. He doesn't catch on at first, even when negative Numbuh One is acting ''wildly'' out of character, being cowardly to Lizzie and even revealing some of the evil plan. That's the "parody" part. The "playing straight" part comes into play because Numbuh Four does eventually figure out the switch... because of negative Numbuh Three's slip-up, not negative Numbuh One's. Specifically, negative Numbuh Three has a mean and nasty look in her eyes, which Numbuh Four knows, as her ''friend'', is something that would never happen with the real, sweet-hearted Numbuh Three (even when Numbuh Three gets ''angry'' it's out of hurt feelings and not cruelty). Ergo, Numbuh Four correctly concludes, they must be from a negative universe or something! In the same episode, Numbuh One realises his girlfriend is an imposter using the same method.
** When Numbah One is trapped in a LotusEaterMachine, he sees through the ruse when he notices Numbah Four swimming in a pool. The real Numbah Four can't swim.
* In the ''{{WesternAnimation/Darkwing Duck}}'' episode "Battle of the Brain Teasers", Launchpad initially doesn't believe Gosalyn when she informs him that hat-shaped aliens that have taken over the bodies of Drake Mallard and Honker, even after seeing them with the hats. It's not until the hat that's taken over Drake has him change into his Darkwing Duck outfit -- without his regular hat -- that Launchpad becomes convinced, because the hat-shaped alien doesn't match the outfit and "DW would never wear a hat that clashes with the rest of his outfit".
* Averted on ''WesternAnimation/FamilyGuy''. Lois is being held at gunpoint by Diane Simmons, and she tries to signal to Peter that something is wrong by calling him "Pete" (something she never does), while Peter does question it, he quickly ignores it and leaves so he can listen to music in the car.
* This was how Cosgrove discredited an evil clone in ''WesternAnimation/{{Freakazoid}}'': he asked if the clone wanted to [[RunningGag go to a Yakov Smirnov festival]]. The clone said "no". (Compare that to Freakazoid's usual "DO I!")
* In the ''WesternAnimation/{{Futurama}}'' episode "Law and Oracle", Fry is able to tell that Pickles is deceiving him when he shows Bender sharing strong malt liquor with the crew of Planet Express (which, though harmless to robots, is deadly to humans). As Bender is an UnsympatheticComedyProtagonist, he would not share it with anyone.
* Goliath uses this to his advantage in one episode of ''WesternAnimation/{{Gargoyles}}'', when a replicator called Proteus has made himself the double of Elisa Mazza. Unable to tell which is the real Elisa, he inquires whether she ever had any doubts about him -- a reference to a conversation they'd had earlier in the show. One of the Elisas immediately replies that she never doubted him, and he knows that she's the fake because he's perfectly aware that Elisa had doubted him.
* In the ''WesternAnimation/GoofTroop'' episode "Frankengoof", [[FrankensteinsMonster Frankengoof's monster]] looks very similar to Pete in Halloween makeup; so similar that his family initially mistakes it for him. Eventually they realize that the monster isn't really Pete because he's nice and willing to take responsibility, while the real Pete is a {{Jerkass}} and a LazyHusband. The episode ends with his family deliberately abandoning him and bringing the monster home instead.
* In one episode of ''WesternAnimation/GravityFalls'', Wendy is fighting a shape-shifting monster who is disguised as her. When Dipper has to figure out who is who, he asks for a sign. The shapeshifter smiles at him flirtatiously, while the real Wendy mirrors the "zipped-lip" gesture she gave earlier, in dead seriousness. That was the only clue Dipper needed.
* In ''WesternAnimation/JackieChanAdventures'', when Jackie is in the same room as a clone, [[GuileHero Jade figures out the fake by asking if she can go to a theme park]]; the fake says yes, while the real one replies no.
* Played humorously straight in the ''WesternAnimation/JohnnyBravo'' episode "Johnny's Inferno". Johnny is possessed by a junior devil named Derek who plans on committing evil deeds, but they stop for lunch at Pops's diner first. Johnny orders a plate of entrails and offers a credit card as payment. Pops immediately realizes something is very wrong, but not because of the odd food -- it's because Johnny "tried to ''pay for his meal!''"
* In one episode of ''WesternAnimation/MaxSteel'', [[BigBad John Dread]] hacks into Max's coms signal and replaces Berto Martinez as Max's MissionControl. Max figures this out due to Dread referring to Max as "hombre" and "amigo", in contrast to Martinez's standard term of affection, "hermano".
* On an episode of ''WesternAnimation/MenInBlack'', J instantly realized that a robot was impersonating K, because K would never had laughed at any of his jokes.
* ''WesternAnimation/MyLittlePonyFriendshipIsMagic'':
** In the season 2 finale, Twilight realizes that Princess Cadence is [[NotHimself not herself]] when she doesn't respond to her secret handshake and becomes even more suspicious when she sees Cadence acting unusually rude and selfish.
** Later on, Twilight encounters the real Princess Cadence who proves her identity with the [[CoolBigSis aforementioned secret handshake.]] The two race back to the wedding in time to expose the impostor.
* ''WesternAnimation/ScoobyDooMysteryIncorporated'':
** Freddy and Daphne get impersonated. While Daphne's fake is at least a little believable, Freddie's fake is a textbook example. The rest of the gang didn't really need the secret clue.
** In another episode, Scooby and a gang of other mystery-solving sidekicks find their human friends [[ItMakesSenseInContext supposedly turned into guinea pigs]]. [[spoiler:Scooby knows something's up the moment the "Shaggy" guinea pig violently rejects [[TrademarkFavoriteFood a Scooby Snack]].]]
* Spoofed in ''Sev Trek: Pus in Boots'', an Australian parody of ''Series/StarTrekTheNextGeneration''. Captain Pinchhard (Picard), Cmdr Piker (Riker), Gaudy (Geordi [=LaForge=]) and Beta (Data) are hunting a shapeshifting alien that's roaming loose on the Enterforaprize. They enter a room to find Measley Cruncher (Wesley Crusher) who's just invented a Plot Device which will detect the alien ''and'' save the Enterforaprize for the 47th time! Captain Pinchhard gives a BigNo and disintegrates Measley on the spot.
-->'''Piker:''' [[BigOMG Oh my God]], you killed Measley! ''[All point their phizzer rifles at the captain]'' Only the alien would do that!\\
'''Pinchhard:''' Oh please! [[TheScrappy Don't pretend you never wanted to do it!]]\\
'''Gaudy:''' You know, he's got a point...\\
'''Beta:''' He annoyed me, and I'm an android.
* ''Webcomic/EnsignSueMustDie'':
--> '''Beverly:''' He is my son and I couldn't stand him.
* Parodied in ''WesternAnimation/TheSimpsons'', episode "Midnight Towboy", when Homer is kidnapped and calls his family.
-->'''Lisa:''' Dad? Where are you?\\
'''Homer:''' ''(reading from a cue card held by the kidnapper, bad acting)'' Do not worry, I am working.\\
'''Lisa:''' Working? Where?\\
'''Homer:''' Ask no questions and do not call the police or I will kill me.\\
'''Lisa:''' You sound weird.\\
'''Homer:''' Everything is fine, goodbye forever. ''(hangs up)''
* Happens in ''WesternAnimation/{{Slugterra}}'' when Twist is posing as Redhook. He invites the Shane Gang to discuss things over a glass of lemonade. This immediately alerts the Gang (except Pronto) that this is not not the real Redhook, as Redhook is never that sociable.
* A variation of this occurs in the ''WesternAnimation/SonicSATAM'' series. Sally has been replaced with a robot duplicate, and the robot says a multitude of things she would never say. It's when she replaces a "thumbs up" gesture with Sonic with a "thumbs down" gesture that Sonic gets it.
* In ''WesternAnimation/AdventuresOfSonicTheHedgehog'', Sonic becomes concerned about Tails' safety, so after some false starts finding him a family to adopt him, he finds what he thinks are his real parents. He leaves Tails with them, but then becomes depressed that he's gone. He has a flashback of the parents welcoming "Tails" to their family... and then suddenly remembers that ''he'' gave him the name Tails; Tails' ''real'' parents should have called him Miles, the name ''they'' gave him! Sonic rushes to the rescue; the "parents" turn out to be Robotnik's robotic goons in disguise.
* All-around skewered in the ''WesternAnimation/SouthPark'' episode "Spookyfish", where "Evil Cartman" (actually a sweet and lovable MirrorUniverse Cartman... from a MU where everyone has a goatee and is the opposite personality) and "Real Cartman" fight to avoid being sent back to the MU. When the goatee gets ripped off, one Cartman says they'll just have to send both back to be sure. Wanting "Evil Cartman" to stay, and knowing the "Real Cartman" would never be selfless enough to suggest such a thing, the boys send the other Cartman back... except that Real Cartman anticipates this and trick them.
* In ''WesternAnimation/TheSpectacularSpiderMan'', [[spoiler:Norman Osborn does not apologize]]. The Chameleon would, though.
* ''WesternAnimation/StarWarsTheCloneWars'': In the opening movie, Rex clues Anakin and Ahsoka into the fact that the surviving members of the group of clones have been captured by saying "Anakin, we've held the droids. What is your position?" This clues them in because all clones address Jedi by either "General" for Knights or "Commander" for Padawans, never by name. What's especially impressive about this is that Rex ''[[HeroicWillpower resisted]] a [[JediMindTrick mindtrick]] from Ventress'' in order to do it. He just played along so she wouldn't realize it didn't work.
* In ''WesternAnimation/SuperFriends: The Legendary Super Powers Show'', three Super Friends infiltrate an AuctionOfEvil to get a piece of Gold Kryptonite from ComicBook/{{Darkseid}} by disguising themselves as ice aliens. However, in the auction, Darkseid notices that those "ice aliens" are strangely comfortable at the station's normal room temperature and realizes they are impostors and exposes them.
* On ''WesternAnimation/TeenTitans'', the hero Jericho is possessing Cinderblock to get him and the other good guys into the bad guys' lair. However, he villains are immediately suspicious when "Cinderblock" says "Thank you" to one of their comments -- having never fought these villains before, Jericho didn't realize that Cinderblock [[TheVoiceless doesn't normally talk]].
* In an episode of ''WesternAnimation/TheTransformers'', Megatron builds a clone of Optimus Prime to lure the Autobots to their doom. Just when he manages to convince the others that he's the real thing, they get word that Spike is in trouble. Megatron, trying to keep his plans on track, says that Spike is unimportant, cluing the others in that he's fake.
* In an episode of ''WesternAnimation/TransformersPrime'' Bulkhead noticed something off about his ''"friend"'' Wheeljack and asked him to tell the story of a particular battle. Makeshift, the impostor tells the story perfectly, but manages to get one crucial detail wrong... Bulkhead ''wasn't'' part of that battle.
* When the ''WesternAnimation/WinxClub'' search for the Gem of Self-Confidence, Bloom, Stella and Aisha find themselves facing illusions based on their inner fears. [[spoiler: Aisha faces an illusion of Nabu, and quickly realizes it's not really him when the illusion blames her for his death, which is something the real Nabu would never do.]]
* On ''WesternAnimation/YoungJustice'', Franchise/{{Batman}} calling the Team "kids" helps tip off [[TheSmartGuy Robin]] that [[MindControl something's]] not right.

[[folder:Real Life]]
* The crew of the USS ''Pueblo'', captured by North Koreans, and their "[[http://web.archive.org/web/20071204163149/http://www.usspueblo.org/v2f/captivity/goodluck.html Hawaiian Good Luck Sign]]."
** A captured [[UsefulNotes/TheKoreanWar Korean War]] commander, forced into a confession, gave this: "We paean the great state of UsefulNotes/NorthKorea and its leader." "Paean" is [[https://www.merriam-webster.com/dictionary/paean a real word]], so the North Koreans were able to look it up and confirm its meaning, but it's pronounced very similarly to "pee on", which the North Koreans didn't catch.
* Some biometric fingerprint scanners have a "panic" feature: One of the user's fingers is designated as the "panic finger": In normal conditions the user does ''not'' press it against the scanner to be verified; if they do, it still grants access but also trips a silent alarm (allowing the user to discreetly summon help if he is being coerced into opening the scanner lock).
** Similarly, password-based systems may include a "duress code" that triggers a remote alarm when entered.
** There is a persistent urban legend that if a mugger tries to force you to withdraw money from an ATM, typing your PIN backwards will let the authorities know you are being forced to do it. Contrary to popular belief, while this system has been seriously proposed (and endorsed by many police officers), it has never been implemented in the United States.
** On this same reasoning, many stores have an easy-open formula to open their tills (which silent alarms the police), or a harder version that implies calling a supervisor for everyday issues. Essentially, if you just open the cash register without a purchase, someone will know about it.
** Several home security alarm systems have implemented 'panic button' codes. Upon installation, the homeowner will pick two codes, one to arm/disarm the system normally, and one which functions as a silent alarm, seemingly disarming the system but actually calling for an immediate police dispatch to the home.
* As mentioned in ''BravoTwoZero'', people in the military, particularly special forces who may be likely to be captured, will often agree on a sign that they are being forced to do something under duress. In this book, one of the captured soldiers is forced to make a video message stating that all's well. He is given a cigarette to add to the illusion. His signal that all's ''not'' well is to hold the cigarette differently than he usually would.
* When captured during UsefulNotes/TheVietnamWar, then-aviator Jeremiah Denton communicated to the American audience during a televised interview by blinking in Morse code, spelling out the word "torture".
* One urban legend describes a prisoner of war forced to write a letter to his family saying that he is being treated well. In the letter is a cryptic sentence: "Please give little Jimmie the stamp for his collection." The family doesn't know anyone named Jimmie, so they realize that it must be a clue. They steam the stamp off the envelope, and on the other side is written the truth of the prisoner's condition: "They've cut off my [hands/legs/tongue]."
* Some businesses have, as a standard response to someone making threats, a protocol for calling 911. The employee tells the person they will have a supervisor paged, pick up the phone, dial 911, and then hang up. When 911 calls back, they respond as if talking to a supervisor with simple "yes" and "no" answers.
* Military personnel on guard or patrol duty will typically have a "distress call-sign" which they use in place of their own to discreetly call for help.[[note]]For example, if his call sign was "Guard3", he would say over the radio "Dispatch, this is Guard7", which would alert the dispatcher that he is in trouble but can't say so.[[/note]] Another common tactic is to have a very specific but seemingly innocuous statement (Such as "Is Frank still dating Lisa?") which, when said, will alert their allies that something is wrong.
* Arrested by the Nazis during UsefulNotes/WorldWarII for suspicion of hiding Jews in her house, [[http://en.wikipedia.org/wiki/Corrie_ten_Boom Corrie ten Boom]] received a letter from her sister with bad news (their father's death). She then noticed the address was written in a hand that sloped uncharacteristically forwards, pointing to the stamp. The stamp had the message "All the watches in your closet are safe", letting her know the hidden Jews had not been found by the Nazis.
** They had that code already. "We have a woman's watch here that needs repairing. But I can't find a mainspring. Do you know who might have one?" was one way of saying that there was a woman in need of a hiding place, but none available. Any references to issues with a watch's face meant a Jew whose features were especially Semitic -- "Do you know someone willing to take on the extra risk?" And "This watch cannot be repaired -- do you have a receipt?" meant "Someone has died. We need a burial permit."
* From a letter by a Jewish family which passed through Nazi censorship:
--> "Dear XXX, let me assure you, all the stories about Jews having to suffer in Germany are nothing but propaganda. We are fine in every way, we are not harassed by the government, and we wouldn't wish to be anywhere else, except maybe with our dear aunt Sara -- Sichrona la olam!" (The latter being a Hebrew phrase roughly equivalent to "May she rest in peace".)
* If the pilot of an aircraft sets their transponder code to 7500 or says 'squawk 7500' over the radio and then does not respond, air traffic control will assume the aircraft is being or has been hijacked. There are also other, confidential, measures taken. In fact, great emphasis is placed on the part of radio training where pilots are instructed how to avoid ''accidentally'' flipping their transponder to 7500 while switching codes.
** Other transponder distress codes include 7600, which translates roughly as "My radio is not working properly"[[note]]The transponder functions separately from the voice-based radio, so it's possible for one to be busted and the other to be working fine.[[/note]], so the [[MissionControl Air Traffic Controllers]] will know why you don't respond to them on the radio, and 7700, which is a general-purpose DistressCall.
* In UsefulNotes/WorldWarII, when the Japanese let captured American soldiers speak on the radio to assure the troops they were being well-treated, they often said things such as they were allowed to keep their clothing -- that is, they were still dressed in whatever rags their clothes were after battle and POW camp. This were improvised, but still conveyed enough to the Americans that they were not being treated well.
* At the National P.O.W. Museum (496 Cemetery Rd, Andersonville, GA), by the Andersonville [[UsefulNotes/TheAmericanCivilWar civil war]] prison, there are a number of video screens to watch, including one screen showing black and white footage from UsefulNotes/WorldWarII Japan. In this video there is a prisoner leaning on a railing, facing generally toward the camera. The man is unobtrusively giving the Hawaiian good luck symbol, so this gesture in film pre-dates UsefulNotes/TheKoreanWar. Museum staff were unaware of this.
* It's very obvious when someone else is doing something on another person's Facebook, or MSN.
** There was a meme for a while of hacking, say, Bobby's Facebook and making his status "hi my name is Bobby" as a signature.
** Teens who frequently visit chat rooms and message boards normally only use general internet slang when they aren't being closely supervised by suspicious parents. When they ''are'' being closely supervised by suspicious parents, they use obscure or community-specific slang much more frequently, to let the other posters know that they're being watched. Sometimes, more directly, they'll say something like "P.O.S." -- "Parents Over Shoulder".
* The Special Operations Executive (SOE), which sent many agents into occupied countries during UsefulNotes/WorldWarII, provided them with duress codes and other security checks that would blend in with the normal text[[note]]such as using non-obvious codewords and including/not including certain punctuation characters in certain points of a message[[/note]]. However, when the Gestapo forced captured "pianists" (wireless operators) to send false messages or attempted to use captured equipment themselves SOE headquarters would infamously ignore their own security protocol and keep trusting the communications[[note]]one problem being that radio operators (hastily trained and transmitting under difficult circumstances) would often make mistakes anyway, making it harder to spot actual duress codes[[/note]]. On one occasion, the [[WhatAnIdiot British contact in England told the agent attempting to sound the alarm that they made a mistake]]: "That's the duress code, you need to remember not to use that." Needless to say, things went downhill from there, with many agents being delivered directly into the hands of the Gestapo after the SOE had arranged drops with a captured agent or an enemy operator on the other end.
* It is generally extremely obvious when a tourist is visiting another country and trying to blend in. For example, being in Australia and greeting everyone with "G'day" and putting on a very Crocodile Dundee accent will make you stand out as a foreigner; while some Aussies do say "G'day," most just say "Hello" or something similarly universal. As for the accent, since most tourists are at the cities (sorry middle of Australia), the accent is not as pronounced as Crocodile Dundee. Also, Aussies tend to crack jokes about tourists who do this, and it might be the same elsewhere (like a person wearing a "I <3 New York" t-shirt in New York) so it's probably not the best idea to try and imitate them.
* A news story in the mid-2000s (powerfully dramatized in [[https://www.youtube.com/watch?v=rTJT3fVv1vU this Super Bowl commercial]]) had a 911 dispatcher answer a phone call from a woman who, after giving her address, began placing an order for a pizza. The dispatcher was confused at first, but as the woman kept talking, he realized that she was being abused and needed to send a coded cry for help. He was able to recognize the distress in the woman's voice and send assistance.
* A literal case on the set of ''Series/DoctorWho''; when filming [[Recap/DoctorWhoS26E1Battlefield "Battlefield"]], there was a scene where Sophie Aldred (Ace) was trapped in a rapidly-filling water tank, and instructed to bang on the glass. Unfortunately, the glass cracked, and water was getting dangerously close to some electrical equipment. Creator/SylvesterMcCoy noticed the impending danger, and had seconds to warn the crew, but had to do it in a way that wouldn't be mistaken for the Doctor. He managed it with a [[PrecisionFStrike Precision S Bomb]], and Aldred was saved in the nick of time.
* People battling depression tend to be listless, gloomy, unmotivated, or feeling other emotions that convey depression. Because depression is not something one can just get over by themselves in a day, it can look quite unusual for the affected person to suddenly display more positive feelings. For people who deal with handling people affected by depression, someone suddenly becoming happy (or at least more at ease) is a ''serious'' red flag indicating the person may be prepared to commit suicide since they've come to terms with it. This is distinct from UsefulNotes/BipolarDisorder, where [[MoodWhiplash depression and happiness regularly switch places]].