->'''Cartman:''' Aha! Kenny! I should have known! Why do you have a picture of Mysterion in your locker, Kenny?! Unless you ''are'' Mysterion!\\
'''Stan:''' Dude, I have a picture of Mysterion in my locker too.\\
'''Clyde:''' Yeah, so do I.\\
'''Cartman:''' What?! Why?\\
'''Clyde:''' I don't know, it's just a cool costume.
-->-- '''''WesternAnimation/SouthPark''''', episode "The Coon"

A standard fixture of the FantasticComedy: whenever the series concept requires that an extraordinary person {{Masquerade}} as [[SecretIdentity ordinary]], there is one person around who suspects them, or has already learned about their secret (usually not every little detail, but enough to see them for what they really are). This character is always the OnlySaneMan -- ClarkKenting, fortunately, still works for everyone else -- making this character [[TheCassandra only look crazy]] if [[YouHaveToBelieveMe they try to expose the protagonist]].

If the character himself is not convinced that they are just hallucinating -- and some of them are -- they become set on getting proof to [[TheyCalledMeMad show everyone else]] that [[TheCuckoolanderWasRight they were right all along]] -- only to [[ButtMonkey fail every time]]. Sometimes the neighbor fancies herself an AmateurSleuth, going so far as [[NosyNeighbor to spy and snoop]] whenever visiting the "undercover" character. They may even set traps to expose the character's {{Masquerade}}. Usually though they have no idea -- or care -- about the trouble they are getting themselves into around the protagonist, so typically the hero will need to save them when they get ''too'' involved. Some have a perfectly logical (though often villainous) motivation, but other seem not to have considered the question [[AndThenWhat "What would happen if you did expose your neighbor's secret, and would you really benefit from this?"]]

This character is usually a [[{{Muggle}} normal human]] in the vicinity from their [[WakeUpGoToSchoolSaveTheWorld civil life]] who has noticed that something is odd or amiss with them -- a NosyNeighbor or a SnoopingLittleKid. If the masquerading subject is in school, the character is quite likely to be a teacher at that school, or a SchoolNewspaperNewsHound. If the show is a WorkCom, it can be a co-worker, often a rival or the subject's immediate manager.

Occassionally, the character will have had an obsession with the supernatural ''before'' they meet the protagonist. They may be a danger that comes from the outside -- TheHunter, an InspectorJavert or the IntrepidReporter.

Often there is a character around who could give weight to their claims, an authority to present their proof to who views with bemused indifference their ranting insistence that something is strange about the main character -- a husband if the character is the neighbour, the school principal if they are a teacher, a more senior manager in a WorkCom. Sometimes a {{sidekick}} whom they [[TheDragAlong drag into helping them]] -- usually an underling, such as a school janitor if or an intern -- is also present.

Contrast/compare SecretKeeper. See also NotSoImaginaryFriend.

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!!Examples:

[[AC:{{Anime}}]]
* ''Manga/AhMyGoddess'': Sayoko noticed how there is something off about Belldandy, and goes to great lengths to uncover her secret. Of course, since Belldandy is a Goddess who CannotTellALie, she simply tells Sayoko the truth. Sayoko never believes her and continues her schemes.

[[AC:ComicBooks]]
* ''Comicbook/{{Fables}}'' did this twice; once when a reporter thought all the folks of Fabletown were vampires; and planned to "out" them to the world. The second time was with Thorne, later [[spoiler:subverted because he's a Fable himself]].
* Ben Urich was this to ''Comicbook/{{Daredevil}}''; in both the comic and the movie adaptation.
* The SilverAge LoisLane would occasionally act this way around ''Comicbook/{{Superman}}'', as would Comicbook/LanaLang around Superboy.
** Also JimmyOlsen.
** Played for black comedy in a one page story in an old superman comic: Clark is reading a book at the Daily planet when suddenly Louis Lane falls from a window. He rescues her without changing his clothes as Clark. Then she tells him this was the only way she would make sure Superman is Clark Kent. Next panel we see another reporter talking to Clark again reading a book:
--> Clark, have you seen Lois?
--> Yes... she fall out of a window.
* Vicky Vale in SilverAge ''Franchise/{{Batman}}'' comics.
* In the comic ''ComicBook/PS238'' a school full of kid superheroes in their civilian secret identity disguises also includes the extremely paranoid Cecil Holmes, who is convinced his school is full of disguised ''aliens.''
** Semi-subverted in that [[spoiler:Cecil turns out to be a metahuman who can detect other metahumans and that was what was fueling his paranoia.]] Ironically, he never manages to spot the ''actual'' alien at the school, Prospero.
* One of these neighbours sicced an [[KnightTemplar occultist]] on the ComicBook/FantasticFour in one issue, mistaking them for witches.
* Tim Drake used his abilities as this to convince Batman that he should become the next Robin.
* ''ComicBook/UltimateSpiderMan'' played with this. Peter's classmate, Kenny "Kong", was typically displayed as the dumb jock type. One day, while lying in his bedroom, he was able to put together the coincidences and realized Peter was Spidey. None of his classmates believed him.
* The ''ComicBook/AstroCity'' story "Knight In Shining Armor" plays it very darkly with the character of Irene Merriweather (a LoisLane Expy), who wants to expose the security identity of the superhero Atomicus so badly that she pulls off immense acts of {{Superdickery}}, like refusing to stop looking (and putting herself and other people in danger as entrapment bait) when the man she believes to be Atomicus (her own coworker) ''gets his house blown up by the Mafia because they got wind of her investigations''. At the end of the story Atomicus is so fed up of her that he exposes his real identity, gives Irene a TheReasonYouSuckSpeech, '''and leaves Earth forever'''.

[[AC:{{Film}}]]
* In ''TheReturnOfHanuman'', Munni noticed that Maruti looks rather different. The other gods were worried that she will expose Maruti's secret that he is actually Hanuman. Fortunately, she didn't even have the will to figure out what's wrong with Maruti.
* In the Richard Donner cut of ''SupermanII'', Lois Lane is this in spades, going even so far as to risk killing herself by jumping out a window and later pulling a gun on Clark and firing at him [[spoiler:(she loaded the gun with blanks)]] just to prove that he is Superman.

[[AC:{{Literature}}]]
* Inverted in Literature/HarryPotter. The Dursleys know full well that there's a whole world of magical people and creatures hidden from {{Muggles}}, and go to absurd lengths to try to pretend it doesn't exist.
* Robert Audley in ''Lady Audley's Secret'' goes to extreme lengths to prove the titular character's secret, as he figures out what it is fairly early on.

[[AC:LiveActionTV]]
* Gladys Kravitz on ''Series/{{Bewitched}}''.
* To a certain degree, Dr. Bellows on ''Series/IDreamOfJeannie'', but more so his wife Amanda.
* Notably absent in ''Series/SabrinaTheTeenageWitch'', much to the surprise of all.
** Until Brad showed up.
* Sergeant Doakes from Series/{{Dexter}}.
** Detective Quinn becomes one as he starts to get suspicious about Dexter. However, he has secrets of his own and the closer he gets to the truth the less willing he is to pursue it further.
* Jack [=McGee=] from the TV show ''TheIncredibleHulk''.
* Elton Pope (and the rest of LINDA) from the ''Series/DoctorWho'' episode "Love and Monsters".
* Eugene Jones from the ''Series/{{Torchwood}}'' episode "Random Shoes" (after his death, Gwen ended up investigating ''him'').
* One ''Series/MontyPythonsFlyingCircus'' sketch takes this to extremes by having two women spy on their neighbours with high-tech surveillance equipment.
* In ''PushingDaisies'', [[spoiler: Oscar Vibinius]] eventually ends up as one of these.
* ''PhilOfTheFuture'': Vice Principal Hackett is convinced that there is something odd about the Diffys. But he is only half right about them. He believes them to be space aliens, but they are actually from the future.
* In the second season of ''Series/MightyMorphinPowerRangers,'' Bulk and Skull became obsessed with discovering the Rangers' true identities.
** Cassidy and Devin in ''Series/PowerRangersDinoThunder'' were like this too (well, Cassidy chased the secret and dragged Devin along with her). They, like their predecessors, had no idea they were going to school with the heroes [[spoiler: until the season finale, where they learn the truth and choose not to reveal it.]]
* Lois Lane in the LiveActionTV series ''TheAdventuresOfSuperman''.
* In early seasons of {{Smallville}}, both Lex and Lionel Luthor suspect something is different about Clark, and go to great lenghts to try and discover it. Later on, in the episode "Hydro" Lois Lane attempts to prove Oliver Queen is GreenArrow. Oliver and Clark manage to convince her otherwise by having Clark dress up as the Green Arrow. In the episode "Identity" Oliver repays the favour by pretending to be the Red-Blue Blur when Jimmy Olsen suspects Clark Kent.
** The first season also had reporter Roger Nixon, who Lex hired to investigate Clark Kent.
* This is basically Vince and Dave's ''job'' in TheSecretWorldOfAlexMack. When Dave finds out later on his own, he realizes that Danielle Atron and Vince are horrible people and becomes a SecretSecretKeeper in relation to Alex.
* In ''Series/YoungDracula'', van Helsing is this to the Dracula family, following the imperative of ''his'' family line. Amusingly, he is a woodwork teacher.

[[AC:VideoGames]]
* Fujimoto the sushi chef seems to be the only one who can see through VideoGame/{{Octodad}}'s PaperThinDisguise.
* Bob Copper in ''VideoGame/MegaManStarForce'' has this as, quite literally, his job description. When he's not trying to find out who Mega Man is, it's because the police force has tasked him to discover the roots of something weirder.

[[AC:Web Comics]]
* Ivan Bezdomny from ''Webcomic/TheWotch'', an intrepid [[SchoolNewspaperNewshound (school) newspaper reporter]] who was dead set on finding the source of the 'Weirdness' surrounding Tandy Gardens.
* George from ''Webcomic/ElGoonishShive'', a comicbook shop clerk who works alongside one of the main characters and was insistently badgering said main character to reveal the backstory of a magical incident that took place near the shop. That is until he abruptly dropped the subject after the main character revealed one of George's assumptions to be wrong and revealing to the audience that the reason for his badgering was to learn something that depended on the assumption being correct and that he didn't actually care for the backstory itself after all.

[[AC:Web Originals]]
* Shin from ''SailorNothing'' -- except that [[spoiler:she ''succeeds'' and becomes a Sailor herself, and her analytical and research skills become a big asset to the other Sailors.]]

[[AC:WesternAnimation]]
* Dib knows that Zim is an alien out to conquer Earth in ''WesternAnimation/InvaderZim''. Unfortunately, despite constantly trying, he can't convince anybody else (except his sister Gaz, but she doesn't care).
* Denzel Crocker of ''WesternAnimation/TheFairlyOddParents'' is constantly out to prove the existence of '''FAIRY GODPARENTS!'''.
* Hans Rotwood from ''AmericanDragonJakeLong''. A teacher of the titular hero, he has an interest in supernatural creatures and is set on proving that Jake is one to the world once he has found out.
* Candace from ''WesternAnimation/PhineasAndFerb'', the older sister of her two ChildProdigy brothers whose crazy inventions only she witnesses: by the time she fetches their mom, it always disappears by some crazy coincidence.
* Mandy from ''TotallySpies'' has acted like this a few times, though the situation is usually solved by LaserGuidedAmnesia. She is the AlphaBitch in the main characters' class who seeks to cross them wherever she can.
* Lt. Mitch Kellaway in ''Film/TheMask'' movie and the animated series is both this and the InspectorJavert. (Not so much in the movie where Stanley ''does'' do illegal things with the mask, such as robbing a bank (he just happened to do so just in front of the goons).)
* Every [[WesternAnimation/{{Animaniacs}} Chicken Boo]] segment contains exactly one character who is aware that the titular character is in fact [[PhraseCatcher A CHICKEN I TELL YOU! A GIANT CHICKEN!]] This guy/gal tends to get ridiculed throughout the episode (or sometimes kicked out) until Boo's masquerade is stripped away somehow. If the wolf-crier was sent away, he/she returns at this point to say, "I told you he was a giant chicken."
* In the ''WesternAnimation/SouthPark'' episode "The Coon", Cartman spends most of the episode trying to find out who Mysterion is. He finally succeeds in having him unmasked when he convinces him that villains would continue to threaten the town unless he revealed himself. But the audience doesn't find out who it was until a later episode. [[spoiler: It was Kenny and he is effectively immortal; waking up the next day after he dies and no one remembers his death.]] Also everyone figures that The Coon is just Bruce Vilanch.
* In ''WesternAnimation/{{Ultimate Spider-Man}}'', Mary Jane Watson, aspiring journalist, seeks to discover Spider-Man's true identity.
* In ''WesternAnimation/BatmanTheAnimatedSeries'', villainous scientist Hugo Strange uses a mind-reading device to find people's dark secrets and blackmail them. This leads to his discovery of Batman's identity, which he [[AuctionOfEvil tries to sell]] to some of Batman's enemies.
* ''WesternAnimation/TheAmazingWorldOfGumball'' Episode ''The Secret'' is dedicated to this trope. While they're locked in the bathroom, Gumball, thinking they're going to die, [[DeathbedConfession admits he's the one who drew a picture in Darwin's book that got him in trouble.]] Just as Darwin is about to reveal a secret of his own, they are set free. Gumball spends the entire episode trying to figure out Darwin's secret, eventually locking them in the bathroom again to get him to say it. It turns out that Darwin lied when he said a sandwich was great, because it was "just good." Gumball, understandably, is furious that the secret ended up being so trivial.
** [[spoiler:[[InfractionDistraction It turns out that "secret" was a lie.]] The real secret was that he and Anais accidentally uploaded a clip of Gumball trying to hip-hop dance and destroying his room in the process.]]
* Roger a.k.a. 'Pink-Eye' from ''{{Grossology}}'' is obsessed with proving that Abby and Ty are Grossology agents and later with becoming one himself.
* Dipper Pines from ''WesternAnimation/GravityFalls'' is obsessed with solving the mysteries of the titular town.
* Max Gibson in ''WesternAnimation/BatmanBeyond'' was this in her first major appearance, trying to figure out Batman's identity just for fun. Later in the episode, she switches her focus to identifying Jokerz to find out who was attacking her, and erroneously fingered Terry aka Batman as a Joker. After sorting out that misunderstanding (and getting her life saved from the real bad guys), Max becomes a SecretKeeper.
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