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There are many things that go bump in the night, secure in the knowledge that their unholy powers can trick the human eye into blindness, allowing them to [[{{Masquerade}} live among and prey on humanity]] with impunity. But their supernatural (and at times [[AlwaysChaoticEvil inherently evil]]) nature means that no matter how complete the deception, they can never truly hide what they are. They may fool the mundane senses, but not the spiritual ones; inanimate objects, [[EvilDetectingDog animals]], [[OracularUrchin children]], TheEmpath or [[TouchedByVorlons spiritually touched]] people can sense and [[YouCanSeeMe see through]] the deception and cause a {{Glamour}} Failure. The HunterOfMonsters and mundane heroes wise to these evil tells will be sure to use them to ferret out the villain from among normal people. Writers love to work these tells into TheReveal when the creature's victim finally puts two and two together. More tragically, a hero under the effects of TheVirus will usually have the [[HeroicBSOD full emotional impact]] of it sink in when they [[TomatoInTheMirror can't see their reflection.]]

These flaws in their façade are usually mixed and matched. So [[OurMonstersAreDifferent your mileage may vary]] depending on the critter:
* [[MissingReflection No reflection]] (usually reserved for vampires, ghosts and TheSoulless). GenreSavvy characters noticing a lack of mirrors ([[HouseOfBrokenMirrors or several broken ones]]) will have this same effect. Depending on the setting, this may include not appearing on film and/or digital cameras, or being inaudible on telephone or recording.
* [[TheMirrorShowsYourTrueSelf True reflection]] (Fae or other glamour users will usually reflect their true image). A modern variation has the true form of glamour users revealed by a security camera, since glamour meant to fool human minds won't work on a [[DisabilityImmunity mindless machine]].
* Animals hate and distrust them (see EvilDetectingDog).
* Physical defect (usually for {{Shapeshifter}}s, [[CloningBlues Clones]], [[ReplicantSnatching Body Snatchers]], or {{Chest Monster}}s). See RedRightHand and MorphicResonance.
** Fairies and demons trying to pass for human were traditionally betrayed by their tails or cloven hooves.
** Anyone who is [[DemonicPossession demonically possessed]] will usually [[TheCorruption grow tiny horns]] or [[TransformationOfThePossessed slowly "mutate"]] to look like the demon possessing them.
** UndeathlyPallor for those who are possessed by ghosts, are turning into a zombie, or are vampires.
* [[FangsAreEvil Mildly pronounced fangs]] (not huge, but big enough for the WolfMan and vampire to stand out; compare CuteLittleFangs).
* [[PointyEars Pointed Ears]]. A staple of vampires, fairies and elves. For vampires, it's presumably to mimic a bat's large ears; for elves and fairies, pointed ears are often stated to resemble the ears of deer (a popular shapeshift for Celtic fairies) or curled leaves.
* [[EyesNeverLie Unusual eyes]]: Red or yellow colored eyes, AnimalEyes or [[HellishPupils vertical pupils]].
** Variation (used in ''Literature/{{Discworld}}'', but based on earlier folklore): the eyes are the only part that cannot be disguised, and reveal the true nature of the being.
* [[CastsNoShadow No shadow]] (usually ghosts and {{Hologram}}s will lack these).
** [[LivingShadow Shadow moves on its own]] (a staple of vampires and ''really'' nasty critters; also of PeterPan).
** [[TheShadowKnows Shadow shows their true form]] (sometimes for shapeshifters).
* Silver burns (silver has [[HolyBurnsEvil reputed anti-evil properties]], so it's fair game for most creepy crawlies).
** [[ColdIron Iron]] does the same (often for TheFairFolk). Sometimes [[DepletedPhlebotinumShells restricted to cold or wrought iron. (i.e. not steel)]]
* Sunlight burns/weakens/[[Literature/{{Twilight}} makes them]] [[BishieSparkle sparkle]] (not restricted to vampires, any strongly evil or supernatural creature will react to sunlight like a marshmallow in an oven).
* [[HolyBurnsEvil Holy objects burn/repel]] (pretty basic, anything holy aligned will repel evil, ''may'' be culture specific and/or depend on having a pure heart or strong faith).
** Variation: The object itself need not be emblematic of the church or God, it just needs to be something the wielder places his faith within.[[note]]One story had a man ward off a vampire with a ''credit card'' this way. The ''Fans'' webcomic had the protagonists subdue a vampire with the Vulcan hand signal.[[/note]]
* Cannot go some places either because [[MustBeInvited they need to be invited,]] or they cannot cross some obstacle that would not hinder a human, such as [[CannotCrossRunningWater running water]], lines of salt or magic circles.
** Or the opposite, they are confined to a defined area (often for ghosts).
* InvisibleToNormals (for ghosts or imaginary friends)

Some supernaturals will drop their glamour on purpose and reveal their GameFace or HissBeforeFleeing. Others will be faced with an ImpostorExposingTest. A MonstersAnonymous group may know good ways to avoid these to blend in with humanity. When this happens on a large scale it's a BrokenMasquerade. See also VirusVictimSymptoms, and TheMirrorShowsYourTrueSelf. Contrast HologramProjectionImperfection, for when technology is involved.



[[folder:Anime & Manga]]
* Anything made of silver burns vampires in ''Manga/{{Hellsing}}''.
** Seras Victoria burns herself when handling silver bullets in the second episode of the anime. Later in the same episode she jokes about burning herself with silverware. It's not clear if this is the case in the manga as well, since she always handles her silver bullets while wearing gloves.
* Subverted in the ''Anime/GhostInTheShellStandAloneComplex: 2nd Gig'' episode "Trans Parent", in which Batou is convinced that a young girl can see through his thermoptic camouflage somehow. He's wrong -- [[spoiler:she's blind, and her sense of hearing is so good in order to compensate that she can pick up on the sound of his movements.]]
* The wolves in ''Anime/WolfsRain'' use some kind of glamour to appear human, but humans can occasionally see through it, depending on their mental condition (for example, Quent sees through the glamour when he's drunk, and Cher saw through it late in the series while in a highly-stressed state). There's also the matter of the wolf tracks they leave behind. There are also a couple of instances where the wolves look human but cast wolf shadows, though this only happens when humans aren't looking.
* Literature/TheCountOfMonteCristo in ''Anime/{{Gankutsuou}}'' appears blurry and out-of-focus in photographs, and his voice cannot be heard in audio recordings.
* Nanami Jinnai in ''Anime/ElHazardTheMagnificentWorld'' gains the ability to see through illusions. However, she sees ''completely'' through, meaning she doesn't notice there is an illusion in the first place: She simply [[IThoughtEveryoneCouldDoThat assumes everybody sees what she's seeing]] until she blurts out something that tips them off.
* ''Anime/{{Pokemon}}'':
** The character Duplica has an inexperienced Ditto that can transform, but retains its own facial features, (such as they were). Her next appearance has a second, undersized Ditto, named Mini-Dit. This one could transform, matching everything but ''size''. This led to appearances by the likes of mini-Onix and mini-Ursaring.
** In ''Anime/PokemonZoroarkMasterOfIllusions'', [[CunningLikeAFox Zorua]] could disguise itself as a human, but its tail would always remain visible and it would hold its hands up in an odd position.
* Medusa in ''Manga/SoulEater'' has a tendency to form slit-like pupils when feeling particularly sinister, often accompanied with a SlasherSmile.
** And one of those 'snakes' of hers forming a forked tongue on one occasion. The above is all the more disturbing when she [[GrandTheftMe possesses]] a little girl.
* Midway through ''LightNovel/ACertainMagicalIndex'', Touma suddenly finds himself in a bizarre world where everyone's appearance has been swapped without anyone else noticing, leaving him the OnlySaneMan for much of the time. However, photographs are ''not'' changed from Touma's perspective (though even television broadcasts are). He identifies the spellcaster responsible by how their appearance in person is the same as in a photo.
* A variation of this occurs early on in ''VideoGame/HarukanaruTokiNoNakaDe'' manga and TV anime. A female ghost, given a beautiful human form by the BigBad, seduces young men who come to visit her, devouring their souls. When [[UsefulNotes/{{Onmyodo}} Yasuaki]] is sent to investigate the case, she tries this tactic on him, only to be informed that [[ArtificialHuman he has no emotions]] that would allow him to appreciate her beauty, and therefore sees her just as what she really is (a skeleton). She does not take it well...
* ''Anime/QueensBlade'': The BlobMonster Melona can perfectly mimic anyone she chooses, but her pupils always retain their [[HellishPupils eerie shape]].
* Rin of ''Manga/BlueExorcist'', the [[HalfHumanHybrid offspring of Satan and a normal human]], would look like an average guy... If he didn't have PointyEars, a tail, a tendency to burst into [[TechnicolorFire blue fire]] whenever he got angry, and an [[HolyBurnsEvil 'allergy' to holy water]]. He's able to hide the tail, the TechnicolorFire, and the aversion to holy water, and [[WeirdnessCensor nobody suspects anything]].
** His classmates' apparent obliviousness is eventually explained: [[spoiler:people with some form of demonic heritage aren't uncommon at all, even in the world of exorcists. The big issue with Rin isn't that he's the son of a demon -- it's that he's the son of ''Satan''.]] Everyone else is justified by the fact that only someone with a [[InvisibleToNormals Masho (demon wound)]] can see demons. That, and his hair is long enough that his pointed ears could go unnoticed...not to mention not many people are going to be staring at someone's ''teeth''.
* An invisible {{Robeast}} in ''Anime/{{Voltron}}'' is betrayed by the fact that it leaves giant footprints, turns visible when struck by an attack, and inexplicably starts casting a shadow towards the end of the episode.
* Once she gains control of it, [[Franchise/SailorMoon Sailor Neptune]] can break illusions with her Submarine Mirror.
* Since her disguise spell takes concentration to maintain, [[{{LightNovel/Slayers}} Filia Ul Copt]] will start dropping aspects of her disguise (such as revealing her tail) when she's emotionally strained.
* Creator/JunjiIto's Manga/{{Tomie}} shows up on film with extra eyes, mouths, or faces in strange places. She also directly manifests these defects when under sufficient stress -- suggesting that she's diseased or a monster seems enough to trigger her physical instability.
* ''Manga/MyBrideIsAMermaid'':
** Maguro, Agitaro and Furiyo's Humanization Transformations are incomplete, leaving them with [[{{Gonk}} literal]] [[http://screenshots.fansub.tv/1014/19/23.jpg fish faces]].
** Octopus Nakajima reverts back to his true form at random.
** Maki's Humanization Transformation is also imperfect, rendering her mouse-sized. Late in the manga, however, she [[MakeMyMonsterGrow perfects it]].

[[folder:Comic Books]]
* In the Franchise/MarvelUniverse, there have been various ways over the years to detect the shapeshifting Skrulls, including superhuman senses, telepathy, magic, and various devices. Also, [[ThisWasHisTrueForm death]]. However, as of the ''ComicBook/SecretInvasion'' storyline, the Skrulls have figured out ways to trick telepaths, magic users, and super-senses, leaving technology (e.g. 3-D Man's special goggles) and improvised tactics (e.g. ComicBook/MsMarvel shooting a whole crowd with a low-level energy blast strong enough to knock down the humans and leave the Skrulls standing). And then Reed figures out a way to reveal the Skrulls ''anyway''. Guess he's not so [[ReedRichardsIsUseless useless]] after all.
* Komodo from ''ComicBook/AvengersTheInitiative'' must maintain some level of consciousness to keep her transformation, otherwise she reverts back to her true form. She does exactly this in one issue when she accidentally falls asleep in front of her teammate Hardball. Inverted in that she's an attractive young woman in her true form, while transformed she's a lizard...thing. But played straight in that [[spoiler:in her human form, she has no legs]].
* An interesting example is Mrs. Vashti, a.k.a. "Spell Syrin", one of the teachers of ''ComicBook/PS238'', and a former superhero. Rather than bother with official clothes, she just walks around in her spandex-tastic superhero outfit all the time, and uses Glamers to appear demurely dressed to others. The reader, however, usually sees her as she really is, and a couple of mystically talented students have also demonstrated the ability to see through it. More interestingly, when mirrors appear, they show us what she appears like to others, in a direct inversion of the classic "The mirror tells the truth" cases above.
* In that vein, Girl (Varied Number) from the ''ComicBook/TopTen'' comic book series uses her color control over her android body to fake clothing. Too bad her commanding officer, a sentient dog, is colorblind. Punching ensues.
* In ''ComicBook/UsagiYojimbo'', this is the manner in which every disguised supernatural creature is revealed. Stan Sakai grounds much of his work in the actual mythology and history of Japan (see below).
* Claudine Renko (a.k.a. Ms. Sinister) has some shape-shifting abilities (as does Nathaniel Essex himself). After capturing ComicBook/{{X 23}} and Gambit in the "Songs of the Orphan Child" arc of Laura's solo series, she tries to put the moves on Gambit by taking Laura's form. She completely fails to match Laura's mannerisms and speaking patterns. Gambit isn't fooled for a second.
* ComicBook/{{Diabolik}}'s [[LatexPerfection plastic masks]] are good for altering the face, and the eye color can be concealed by contacts, but they do nothing to alter the wearer's body build, thus preventing them from masking as smaller or excessively taller people. Also, there are ways to recognize a mask anyway:
** In the early stories the masks would sometime have imperfections, allowing a savvy observer to realize they're facing Diabolik. Diabolik later improved the process, so this method is obsolete;
** Masks made by imitators tend to melt after a while. Diabolik's masks used to melt too, but he since solved the problem.
** Face check. That is, pinch the guy's face and pull: if the skin detaches, it's a mask. Then again, if the lower face is close enough and the guy wears glasses Diabolik will only mask the upper face, confiding on the checker pinching him low;
** Getting the face wet: you can recognize a masked person if you know what to look for;
** Sweat: if the face isn't sweating but everything else is, it's a mask (how a policeman at the airport recognized a masked accomplice of Diabolik: the accomplice was so nervous his shirt was covered in sweat but the face was clean, and once Ginko gave the alarm he knew who to face check);
** The most epic of all: an inventor ''created a device to detect Diabolik's masks''. Of course, Diabolik killed the inventor, destroyed the device and stole the plans in the same story of the debut.
* ''ComicBook/PaperinikNewAdventures'' provide two ways:
** Paperinik is a known user of LatexPerfection (part of [[ClarkKenting how he can hide his secret identity with only a]] DominoMask: nobody can tell he's not wearing a Donald mask under it). However, 23rd century tech can see through them (how Lyla and the Griffin found his real identity: they saw he had no mask aside for the domino one).
** In the relaunch story "Might and Power" Paperinik has a new nanotech suit that can alter his looks. However, it can't alter his ''height'', getting him found out when he tried to infiltrate a meeting of much taller Evronian generals.
* ''ComicBook/TwoThousandAD'':
** ''ComicBook/NemesisTheWarlock'': Nemesis has a spell to disguise himself as a human when he needs to be incognito. During a trip to the past, the historical Torquemada (who is receiving messages from his future incarnation) can briefly catch a glimpse of Nemesis's true demonic form.
** ''ComicBook/JudgeDredd'': The Sisters of Death, the two witches responsible for the creation of the Dark Judges, originally appeared like two young women, but they only used this to hide their ghostly carcass forms. Sister Psiren can actually see them for what they are due to her psychic abilities.
* ''ComicBook/BlackMoonChronicles'': Played for laughs when the hell-lord Pazuzu transforms himself and his demonic minions into an elf prince and his entourage so they can infiltrate a castle. One of the (male) demons who has been transformed into a noblewoman is rather transparent with his boorish body language unbecoming a high lady of the court. His boss incinerates him as a lesson to the others to remember to act their parts.

[[folder:Fan Works]]
* In ''Fanfic/TangledInTime'', there is a variant with actual glamour. Mr. Dragmire [[note]] actually Ganondorf [[/note]] sets a glamour on Link so the latter would look like a young version of himself so he would pass as his son. Only for the spell to take Mr. Dragmire literally and make Link look how he truly looks under the Dragmire disguise.
* In many ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' fanfics, it's common to show the Changelings as always having one aspect of themselves that can't be completely hidden when they [[VoluntaryShapeshifting change their appearance]]. This one aspect varies from fic to fic, including magic aura color (as shown in the canon show), blood color, and/or how they feel to the touch.
* In the ''Fanfic/PonyPOVSeries'', during the climax of the Shining Armor Arc, when [[BigBad Makarov]] has a VillainousBreakdown, he CharmPerson abilities momentarily fail, allowing everyone on the battlefield to briefly see and sense his [[EldritchAbomination true self]].
* In Fanfic/ANewWorldANewWay sidestory ''Swarm'' Naruto the Zoroark's shadow does not change while he is using his Illusions. This is how Emperor Carapace begins to doubt who he really is.
* Changelings in ''Fanfic/BadFutureCrusaders'' can be identified by touch, as their bodies feel cool and lifeless. Diamond Dogs, and for some reason [[CloudCuckooLander Ms. Daydream]] (possibly) are able to detect them merely by looking at them.

[[folder:Films -- Animation]]
* WesternAnimation/{{Megamind}}'s holo-watch allows him to look like anyone it scans beforehand. However, he, apparently, forgot to waterproof it. It also shuts off if he bumps it by accident. Also, while not noticed by any of the characters, [[EyesAreMental his eye color remains the same no matter which form he takes.]]
* In ''Disney/WreckItRalph'', Vanellope's glitching spreads to whoever she touches, causing them to glitch out until released. [[spoiler:When she does this to King Candy, it exposes his true identity as Turbo, which was hidden by the King Candy skin.]]
* In ''WesternAnimation/TheIncredibles'', Violet can make herself invisible, but when hiding in a river, a rather clever Mook throws some sand upstream of her last known position, allowing the distorted flow to reveal her.
* In ''WesternAnimation/{{Coraline}}'', when Coraline begins to rebel, the Other Mother shifts to a tall, skeletal, more exaggerated form. She remains in this form for the rest of the film before the climax (where she takes on her [[OneWingedAngel Final Form]]). What makes this especially creepy is that despite her inhuman appearance, she [[FauxAffablyEvil continues to act like a doting, caring mother]].

[[folder:Films -- Live Action]]
* In Creator/JohnCarpenter's ''Film/TheyLive'' (1988), aliens use a mind-controlling satellite signal to appear human, cloaking themselves from the eyes of Mankind while they take over governments and corporations. A resistance movement forms when someone creates [[CoolShades special sunglasses]] that can filter out the signal before it reaches the brain and allows the wearer to see the aliens as they truly are. [[spoiler:The film ends with the resistance dying but not before destroying the signal's ground station, [[TheUnmasquedWorld breaking the Masquerade]].]]
* ''Film/TheShadow'' (1994) with Creator/AlecBaldwin as Lamont Cranston a.k.a. the mysterious Shadow, the titular character of this movie screen comic book adaption. His powers of deception, mind control and telekinesis are clearly {{psychic|Powers}}, the result of a TrainingFromHell by an ancient mysterious Asian mentor. Only two people can see through his hypnotic deception: his arch-enemy who has similar mental powers (and who can hide whole buildings from the eyes of passers-by), and the [[MadScientistsBeautifulDaughter professor's blonde daughter]] who is a latent psychic herself and who catches a glimpse of The Shadow when she meets Cranston.
** Cranston also lands himself in hot water twice when the villains circumvent his ability to cloud mens' minds. The first time happens in Dr. Lane's lab when one of Shiwan's men begins shining a flashlight around the room, discovering him when the light falls on him and makes him cast a shadow. The second time happens when he tracks down Farley Claymore to a pressure testing chamber, thinking he's been brainwashed into helping Shiwan; the latter starts filling the tank with water, and spots Cranston by looking for signs of water flowing around a person's legs. He ends up getting shot on both occasions. The third time they try this on him, he's discovered a counter: He makes his enemy think that he sees his shadow in multiple places, causing Claymore to waste all his ammunition firing at illusory shadows.
* ''Film/XMenFilmSeries'':
** ''Film/XMen1''
*** Mystique's shapeshifting isn't quite perfect. Her eyes flare yellow if she loses her concentration, and she can't quite mimic the scent of others (making her particularly vulnerable to Wolverine's sense of smell).
*** After "Bobby Drake" convinces Rogue that she should leave the school, his eyes turn yellow, revealing that it was Mystique in disguise. This occurs again with a Statue of Liberty sculpture and [[spoiler:Senator Kelly at the end of the movie.]]
** ''Film/X2XMenUnited'': Mystique can't seem to hide the scars Wolverine left behind on her. Likewise, Stryker isn't fooled when she masquerades as Wolverine. One thing he knows better than anyone is his own work.
** ''Film/XMenDaysOfFuturePast'': Mystique's irises briefly become yellow when she assumes the identity of a Secret Service agent and [[spoiler:Major Stryker]]. Moreover, when she duplicates [[spoiler:Bolivar Trask]], she doesn't get his face quite right.
* ''Franchise/{{Terminator}}''
** Early Terminators (mentioned in ''Film/TheTerminator'') could be recognized easily due to their rubber skin. Because of that the T-800 has an organic coating, but can still be recognized by [[EvilDetectingDog man's best friend]].
** The T-1000 in ''Film/Terminator2JudgmentDay'' could imitate anything it touched, within certain limitations. However, when it's too hot, its mimicking technology got a bit... twitchy. Beyond that, your only clues are his precise movements from the UncannyValley Acting School, and a BluffTheImpostor moment when he's imitating John's foster mother. The dog trick works on the T-1000 as well. Probably because it can imitate shape but not smell.
* In ''Film/PhantomOfTheParadise'', Swan's lackeys always make sure that he's never photographed or filmed. It's revealed that [[spoiler:years ago he made a DealWithTheDevil that allows him to never age; part of the price is that this trope applies to any pictures/film taken of him since the pact was originally made (and videotaped -- the tape is his SoulJar).]]
* In the ''Film/{{Blade}}'' movies, the Glamour Failure ends up being needed. If you are a certain vampire's pet, you gets a tattoo so other vampires know not to eat you. This helps (and oddly hinders) Blade. And relatedly, despite getting all the good bits of vampire powers in his origin (durability mostly) he cannot detect if his adversary is a human with fake pointy teeth. This also comes back to bite him on the ass (pun intended).
* ''Film/BladeRunner'': Replicants are designed to be indistinguishable from real humans by the Tyrell corporation that built them ("more human than human is our motto"). They're immune to both extreme heat and extreme cold, but good luck detecting them on ''this'' unless you don't care about having real humans survive the test... [[MortonsFork Dunk the Witch]] anyone? The Nexus-6 models can come across as emotionally immature due to their short ages (limited to 4 years), but later models had fake memories installed to remove even that restraint. The only reliable way to detect them is the Voight-Kampff test which monitors answers and subtle physical response to emotional questions.
* In ''Film/GalaxyQuest'', Fred Kwan had been making eyes at the StarfishAlien that's disguised as a pale-looking human. Eventually, the two finally kiss, and she lets some of her tentacles out from beneath the illusion. Subverted in that, instead of repulsing and frightening him, it seems to turn him on even more, and they get right into it. Though bystander Guy is repulsed.
-->'''Guy''': Ohhh that's not right!
** I think it's more because of what she was ''doing'' with said tentacles that grossed him out.
* In ''Film/{{Thor}}'', [[spoiler:Loki]]'s true nature as a [[spoiler:half-Frost Giant]] is revealed whenever he touches another member of his race or is exposed to their technology. Played with in that [[TomatoInTheMirror HE didn't even know his true form]] until the first time this happened.
* Played with in ''Film/InterviewWithTheVampire''. Louis steps under a bright light to convince Daniel of his ''true'' nature, but after a moment of shock, Daniel simply rationalises that away. Eventually he is forced to use superspeed to drive the point in.
* In the second and third ''Franchise/DieHard'' films, the first clue that the bad guys are, well ''bad guys'' is they are wearing combat boots with casual or business dress. In the second one [=McClane=] picks up on this and follows them into the luggage room (and goes on to expose their entire plan), the the third it's [[TooDumbToLive noticed by a cop who completely shrugs it off]].
* In ''Film/TheHobbitTheDesolationOfSmaug'', Thranduil, the elf king of Mirkwood, appears quite normal and handsome if [[UncannyValley somewhat]] [[TheFairFolk inhuman]]... until he starts angrily ranting about a previous encounter with a dragon. Suddenly [[TwoFaced about half his face melts away]] and one of his eyes turns milky white, as if it has been blinded. This lasts for several seconds until he regains control of himself and the illusion snaps back into place.
* In ''Film/{{Oculus}}'', the illusions created by the mirror don't show up on camera. This means the characters can beat the illusions with a modern cellphone (not that being yelled at by ghosts freaks them out any less)
* ''Film/{{Labyrinth}}'' managed to do this with a too perfect illusion which helps Sarah remember she has to save Toby from the goblins. It probably would've worked had it not contained [[spoiler: a copy of the play she was working on.]]
* In ''Film/TheLastWitchHunter'', when inspecting 36th Dolan's house following his death, Kaulder checks it for earth magic and the entire illusion of peaceful household is immediately shattered, revealing that the place was raided and the Dolan tortured.
* ''Film/KullTheConqueror'': Queen Akivasha looks like a smoking hot witch for most of the film, but when the time to replenish her strength in the hellfire nears, her hand already turns into a demonic claw when she gets angry at General Taligaro.
* ''Film/{{Halloweentown}}'' had Halloweentown High where the human students turn out to be [[spoiler: monsters such as a WolfMan, a cute fairy girl, a [[CuteMonsterGirl cute troll girl]] and an ogre]].
* ''Film/TheHauntedMansion'' had [[spoiler:Emma being a ghost when she started floating and becoming [[MonochromeApparition blue]] and the rest of the "humans" are still ghosts]].

* In Breaking Dawn of the ''Literature/{{Twilight}}'' series, when [[spoiler: the vampiric Bella meets Charlie for the first time after having been turned]] Alice tells her that [[spoiler: she should wear contact lenses so Charlie doesn't notice the difference in her eye-colour, but the lenses would only work for a few hours before the venom in her eyes disintegrated them, after which she'd have to change lenses.]]
** Edward and the vampires in the books [[spoiler: not only burn or get harmed in the sunlight, but instead sparkle]].
* In the ''Literature/ModernFaerieTales'' one of the characters in ''Valiant'', Ravus (a troll) explains that no glamor is perfect and some trait of the faerie remains, e.g cloven hooves or tails or backwards feet. (In his case, he still has black and gold eyes.) In ''Tithe'', Kaye sees her true, unglamoured reflection in a mirror briefly, later explained when Roiben says glamour could be seen through out of the corner of your eye.
* The Literature/{{Discworld}} gods, despite their reality-altering powers, cannot change their eyes. Said eyes always reveal something about their true nature.
** In the novel ''Discworld/ReaperMan'', there's a scene where a child sees [[TheGrimReaper Death]] in his true form as a skeleton man, thus showing that his power is weakening, whereas Death is able to make adults see him as human (or they at least convince themselves they aren't seeing a skeleton). Blacksmiths (even Death's horse needs shoeing) use blindfolds when the time comes. Knowing Death is hanging around is a pretty scary proposition.
*** Death's glamour relies on a forced augmentation of the normal human WeirdnessCensor: he convinces a person that they cannot possibly be seeing what they are, and so the brain makes up imagery that fits this impression. People who have a reason to see through the illusion or who already know what they're looking at aren't fooled. One time, Death appeared on a stage, and everyone could see him because they were ''expecting'' a character based upon him.
*** And cats.
*** Also wizards and witches, who not only are trained to see things as they really are (much harder than seeing what isn't there) but are entitled to a personal visit when their time comes so are fully aware of his existence.
*** And children -- the aforementioned child could see his true form because really young children have no WeirdnessCensor, so she doesn't know that a skeleton person is impossible.
** In ''Discworld/LordsAndLadies'', those who get close enough to [[TheFairFolk the elves]] or who are wearing or carrying enough iron can see through the glamour they cast and notice that they look... well, ''alien''. Dwarfs, trolls and animals (such as everyone's favourite sentient orangutan, The Librarian) get this ability for free. Dwarfs and trolls go into "crush, kill, destroy" mode on sight of an elf. It's unclear why this is the case though there are theories: the Librarian routinely handles hostile magic, Dwarfs routinely handle iron, and Trolls likely have a lot of iron-based minerals in their body composition.
*** The Glamour of the Elves is an active power they must concentrate on to keep it working. If you knock an elf unconscious, the Glamour vanishes.
*** Elf glamour otherwise works like that of FairFolk. They don't see in the usual way, and iron tends to mess up their perception. If you're wearing iron, you're pretty safe; if ''they're'' wearing iron, [[OhCrap they're screwed]]. Of course, the resident blacksmith has no trouble with them. Granny also notes that modern Discworld residents, like those in Ankh-Morpork, have "iron of the mind": in other words, they're so jaded and skeptical that glamour wouldn't affect them; thus why elf encounters tend to stick to the more-rustic Ramtops.
** Discworld/WitchesAbroad states that no matter what, any transformation spell has a Glamour Failure; EyesNeverLie. This is why [[spoiler: the Duc and the Sisters]] have to keep their eyes covered.
** In Discworld/TheWeeFreeMen dromes create worlds out of people's dreams to trap them in. The only problem is they have a little trouble with mimicking human speech and music.
** Computers -- [[MagicalComputer whether they run on magic like Hex or not]] -- aren't easy to fool in any of Creator/TerryPratchett's works; even if it's just a throwaway line, they ''will'' see through glamour and respond appropriately. Specific examples include a military base's automated security system raising the alarm when Death and company enter an off-limits section in ''Literature/GoodOmens'', or a computer chitchatting with SantaClaus in a short story.
* In Nathaniel Hawthorne's story ''Feathertop'', the title character is a scarecrow with a pumpkin for a head who, due to a witch's spell, is made to appear as an elegant nobleman. When he first goes into public, adults are praising him, but it's mentioned that a small child "keeps babbling about a pumpkin" (and a dog cringes and howls). Later, Feathertop sees himself in a mirror and realizes he's not human and can no longer live with himself.
* In ''Literature/TheChroniclesOfThomasCovenant'', no shapeshifter can change [[RedRightHand their eyes, which may be highly unnatural in color.]] On that basis, occasional Glamour Failure is not that surprising.
* In Robert Bloch's Franchise/CthulhuMythos story "Shadow from the Steeple", the protagonist confronts the man he believes to be possessed by the god Nyarlathotep, noting that his skin has turned darker. The man explains this has been caused by exposure to radiation (he was a nuclear physicist), but when the protagonists doesn't believe him, he turns off the lights, causing his body to glow with unnatural light, and causing the protagonist to die of a heart attack.
* A variation of this shows up in Mike Resnick's science fiction novel ''Literature/SantiagoAMythOfTheFarFuture'', although that is more due to a lack of knowledge on the villain's part. In order to kill the bounty hunter Sebastian Nightingale "Songbird" Cain, the assassin Altair of Altair somehow makes him hallucinate that he is back on his home planet of Sylaria being asked by someone he cared about to help her across a brook (as a lure to get Cain close enough to Altair for her to stab him). At the last moment, he shoots her and tells her corpse, "There aren't any brooks on Sylaria."
* ''TabletopGame/Warhammer40000'':
** In this universe, daemonhosts (a daemon [[SealedEvilInACan sealed in the body of a human]] by means of occult rituals and symbols) generally resemble the person whose body they're possessing, but with distinct physical changes that identify them for what they are. For example, in the final ''Literature/{{Eisenhorn}}'' novel ''Hereticus'', Inquisitor Eisenhorn notes that while the daemon Cherubael has made all the usual physical alterations to its host body -- small horns, glossy golden skin, blank eyes, and claws -- the daemonhost still bears a chilling resemblance to [[spoiler:his old friend Godwyn Fischig]].
** In Creator/DanAbnett's ''Literature/BrothersOfTheSnake'', a squad of marines finds themselves fighting foes that can ''only'' be seen with the naked eye; all their equipment will not recognize them. They bare their faces and win, though several die because of the vulnerability. Later, a Chaos daemon infiltrates a Chapter House. After one Marine recognizes it and kills its host, it escapes, but a second one manages to recognize it. (It also manages to make the rest of the House believe that the first Marine was raving in his cell, but the second one manages to see that in fact, the man is sitting there quietly, and talks with him.)
** In the ''Literature/GauntsGhosts'' novel ''Ghostmaker'', [[spoiler:an Eldar Farseer is manipulating the memories and perceptions of the Tanith First and Only, making them believe that they are back on their doomed homeworld, fighting for its survival]]. The illusion isn't perfect, however, as several characters get the sense that something is wrong, and eventually the glamour fails when [[spoiler: mildly psychic teenager Brin Milo looks at a disguised Eldar warrior through the appropriately-named "Mad" Larkin's [[SeeThruSpecs sniper scope]], revealing that the tall, thin "Tanith" with white and red hair is in fact a [[SuperSoldier Dire Avenger Aspect Warrior]]]].
** Literature/CiaphasCain's NumberTwo Jurgen is a blank, a psychic null that severely disturbs psykers and daemons alike. One story has Cain and Jurgen hunt down Nurgle cultists into a private girls' school, the students throwing themselves onto their rescuers, and would have sacrificed all of them if Jurgen hadn't been there to block the glamour. Another had an entire squad ready to murder each other (Cain included) for talking to the love of their life, then Jurgen came along, dispelling the glamour to reveal a rather unattractive Slaaneshi madam, who was promptly shot by Cain.
--> Impersonating an Inquisitor is a capital offense.
* In Creator/StephenKing's story ''The Ten O'Clock People'' (found in ''Literature/NightmaresAndDreamscapes''), only very light smokers can see the "bat people" who are steadily taking over. Non-smokers and heavier smokers alike simply see humans where the titular group sees the monsters.
* Although in ''Literature/JonathanStrangeAndMrNorrell'', TheFairFolk are TheBeautifulElite, in some tales from the story collection set in the same universe ''The Ladies of Grace Adieu and Other Stories'', they and the other creatures they consort with are shown as actually being monstrous and their fabulous palaces are similarly an illusion hiding squalor.
** There are subtle hints in the few descriptions of Lost-hope in ''Literature/JonathanStrangeAndMrNorrell'', for example, there are tapestries made of skin. It's never commented on and is probably quickly forgotten by the average reader.
* Several stories in C.B. Colby's ''Strangely Enough'' feature animals detecting the unusual and supernatural. "Black Knight of Canterbury" has a dog detecting the passing of a ghostly knight, and in "The Frightened Dog" the title animal detects the approach of a weird threat before the humans he's with do.
-->'''Colby:''' Perhaps it is true that dogs can see what we cannot.
* Creator/RodSerling's ''Series/TheTwilightZone'' anthology, story "The Avenging Ghost". A Great Dane named Duke is able to detect and see the ghost of his dead master before the humans with him can.
* In Carrie Vaughn's ''Literature/KittyNorville'' series, dogs can detect lycanthropes. Said dogs are not of the [[EvilDetectingDog evil detecting variety]], since they go berserk [[DarkIsNotEvil even in the presence of the titular heroine]].
* The main character of ''Peter Schlemihls wundersame Geschichte ("Peter Schlemihl's Remarkable Story")'' [[DealWithTheDevil sells his shadow]] in exchange for great wealth, but is shunned by the rest of society for not having a shadow.
* Rather inverted in ''[[Literature/TheObsidianTrilogy The Outstretched Shadow]]'' by Creator/MercedesLackey and James Mallory. In their true form the demonic creatures known as [[NamesToRunAwayFromReallyFast the Endarkened]] possess red skin, horns, and [[AnimalEyes catlike yellow eyes]]. Neither the Endarkened or their works[=/=]creatures[=/=]spells can withstand the touch of a Unicorn even were one [[VirginPower chaste and celibate]] enough for a unicorn to let touch it without trying to kill them. So when a woman with red skin, horns, and catlike yellow eyes is cowering away from you ''against a unicorn you personally know'' (who is sitting there rather calmly and looks more annoyed with you than her) then it is clear that Something Strange Is Going On.
* In ''Literature/TheMoorchild'', one can see through the FairFolk's glamour by applying Folkish ointment to the eyes.
* While her whole glamour was probably much more extensive than that, Lena in ''Literature/NightWatcher'' is outed as a vampire when her lover notices that she reeks of blood as soon as her mind control fades.
* In the ''Literature/TwelveHouses'' series, moonstones burn the skin of and temporarily take powers away from (most) mages, such as showing a shapeshifter in his/her true form. This is a problem where mages aren't liked very much and gets the heroes in big trouble on occasion. Senneth is powerful enough that she actually wears moonstones, though she ''is'' weakened by them.
* Mac from the ''Literature/FeverSeries'' can see through any Fae's glamour. It's just one of the reasons they're so eager to kill her.
* In a series as heavy on the supernatural as ''Literature/TheDresdenFiles'', it's only natural for this trope to show up on occasion.
** Vampires of the Red Court can be forced to drop their flesh mask by exposing them to True Sunlight, presumably because they can't maintain the focus to keep it up.
** When a vampire of the White Court is about to be controlled by its Hunger, silvery flecks show in their eyes.
*** White Court vampires also shine like porcelain when using super strength and their blood is pinker than human blood.
** Vampires and many other magical creatures have issues [[MustBeInvited crossing Thresholds uninvited]]. Black Court Vampires can't cross them at all, and a Red Court faces agony if it tries. Only a White Court can do so in reasonable safety as long as they're willing to keep their Hunger bottled up for the duration.
** Faerie glamour can be seen through by a wizard's Sight or by using magical ointment on your eyes. Or you can just throw a nail at the fairie in question and watch them drop anything and everything to get away from it; even the strongest of faeries are vulnerable to iron's touch, which breaks through their magic and burns on contact.
** As per the RPG rulebook, anyone with some magical talent gets some sensitivity toward others' supernatural natures, particularly with physical contact. While {{Muggle}}s might walk right by a Red Court vampire without knowing about it, if a wizard did the same they'd at the least know ''something'' was up.
** Most non-human creatures don't have souls, allowing a wizard who looks in their eyes to know they're not human, even if they can't tell exactly what they are.
*** In addition, wizards get an ability called the Sight, or the Third Eye, which allows them to see the true nature of whatever they are looking at, cutting through all illusion and glamer. However, you can never ever forget what you see with the Sight, and some of the things so seen can really screw with your mind. In one case, Harry takes a look at a particularly nasty critter, and its true form is so horrid that it gives him pause whenever it comes to mind up to three books later.
** The one coplete inversion is Harry's cat, Mister, who is the only thing Harry has ever seen which looks ''exactly'' the same to his Third Eye as to his normal vision.
* In Creator/RobertEHoward's Franchise/ConanTheBarbarian story "Literature/TheScarletCitadel", Pelias scares away a giant snake by letting it look at him. Conan is very afraid that it was an [[EvilDetectingDog evil-detecting snake]].
-->''"The scaled people see what escapes the mortal eye," answered Pelias, cryptically. "You see my fleshly guise; he saw my naked soul."''
* An auditory example: in the third novel of ''Franchise/SentouYouseiYukikaze'', JAM prevented humans from perceiving machines. Rei realized this when he heard the noise cancellation system emitting anti-phase engine noise.
* [[Literature/DeltoraQuest Ols]] can be identified by the mark of the Shadow Lord somewhere on their bodies, and by their form wavering once every three days. Inverted for Grade 3 Ols, whose shape shifting is perfect enough that they even die like humans.
* At least once in ''Literature/{{Animorphs}}'', an arrived Andalite is easily identified by the heroes due to her uncontrollable reaction to the food she's devouring.
** In the [[Series/{{Animorphs}} TV series]], controllers would often be betrayed by their habit of ear-scratching, but this did not appear in the books.
** Also, when Marco morphs the wolf spider, he can see through the Chee hologram due to the spider's ultraviolet-capable vision. Before this, they key in on Erek because their dog morphs smell absolutely no scent at all on him.
** Controllers can often be picked out by the revulsion and hatred in their voices and actions when they or someone else says "Andalite!" The kids can't reveal that they know what an Andalite ''is,'' so this is never used as a means of picking bad guys out of a crowd. In fact, a Controller once says "Andalite" to see if one of the kids was an Andalite infiltrator (the Controllers think they're looking for Andalites and not humans. The heroes would ''very much'' like to keep it that way.) but she seamlessly replies that yes, more lighting would be good.
* In ''Literature/{{Paranormalcy}}'', Evie's main ability is that she can see underneath paranormal creatures' glamours. She sees both their glamour and their real self.
* The Creator/DeanKoontz novel "Twilight Eyes" features a protagonist whose psychic talent is to see the true nature of the shapeshifting creatures who live among humans. Interestingly, he had this ability from birth, so it took him many years to realize that hairy, wolf-pig people weren't just another ethnic group.
* The antagonist of the ''Literature/ChantersOfTremaris'' series uses high-pitched MagicMusic to cast spells of illusion to confuse or incapacitate those who hear it. This makes TheSmartGuy, Trout, very useful, as he is partially deaf and can't hear high noises, so the spells fail to affect him.
* Demons in ''Literature/FaeriesOfDreamdark'' have two tells: they leave rooster-shaped tracks irregardless of the shape of their feet, and their [[VoluntaryShapeshifting humanoid guises]] never have the correct number of joints in the fingers.
* In Creator/JohnMilton's ''Literature/ParadiseLost'', the mere touch of Ithuriel's spear, and its celestial temper, forces {{Satan}} back into his true shape.
* In ''[[Literature/SmokeAndShadows Smoke and Mirrors]]'' by Creator/TanyaHuff, Tony, being a wizard, can see through Stephen and Cassie's glamour once he views them through a mirror.
* In ''Literature/DoctrineOfLabyrinths'', Eusebian wizards can disguise themselves with magic, but [[TheMole Lieutenant Vulpes]]'s glamour slips at a soiree, leading to TheReveal that he's really [[spoiler: Isaac Garamond]].
* Invisibility in ''[[Literature/ZeusIsDead Zeus Is Dead: A Monstrously Inconvenient Adventure]]'' works pretty well when used against humans, but gods can still spot other invisible gods if they concentrate.
** It's not just invisibility, either. Hermes spots Apollo, despite his appearing in disguise, because Apollo apparently has a habit of re-using faces.
* In ''Literature/TheNekropolisArchives'', vampires look human, but cast no [[MissingReflection reflection]] or [[CastsNoShadow shadow]]. Demons can change their form to disguise themselves, but they can't alter their kaleidoscopic eyes.
* In ''Literature/TheBartimaeusTrilogy'' a Glamour is one of many tricks that can be used by magicians. Get snared by a Glamour and you'll be sitting slack-jawed staring at something you believe to be a delicious feast as the magician closes in on you and takes you as a helpless captive. And if you so much as touch any of the supposed feast, then you're done. However, a spirit of decent quality can resist the effects of a Glamour and can direct the magician controlling them on how to shake off its effects as well.
* MissingReflection is inverted in Sergey Lukyanenko's ''[[Literature/NightWatch World of Watches]]''. Vampires can glamour the minds of humans to hide themselves from sight. This does not work on Others, who can easily see through these mind tricks. The only way for a human to see a hidden vampire is to look at a reflection, as glamour only works in direct line-of-sight. Video cameras work fine as well.
* Water nymph Lila in ''Literature/{{Below}}'' looks like a pretty, lost young woman, but her disguise falters as she's discomfited by Brenish's increasingly shrewd suspicions—he's a better liar and has enough book knowledge to figure out what she is. Her voice goes feral for a moment; once she accidentally shows her nictitating third eyelids; and after suffering a burn to her hidden stinging tail, its perfect camouflage partially breaks down. When unconscious she slowly fades back to her natural appearance.
* In ''Literature/{{It}}'':
** The titular creature takes many overtly supernatural forms but its "Pennywise" persona, which is meant to pass as a normal man in a clown suit, has subtle flaws which reveal its true nature. Many characters note that Pennywise CastsNoShadow, does things gravity shouldn't allow, and frequently changes eye color. People who see Pennywise at the same time also sometimes note that [[AppearanceIsInTheEyeOftheBeholder he did not appear exactly the same way to each of them]], which further breaks the disguise.
** Taken further when It, a creature who embodies and preys on fear, appears to Patrick Hockstetter, whose distinct insanity means that he isn't afraid of anything whatsoever. He sees It as an indistinct, semi-liquid figure, as though It honestly doesn't know how to exist around him.

[[folder:Live-Action TV]]
* ''Series/{{Angel}}'': Jasmine has a NightmareFuel face (rotten, giant eye-sockets crawling with maggots) that is only visible to [[spoiler:those inoculated with her blood]] as well as [[spoiler:her father, Connor]].
* ''Series/{{Battlestar Galactica|2003}}'': Humanoid Cylons are very difficult to detect in isolation, but once more than a few get together it gets much easier as there are many copies, but only twelve "models". Their very existence is sniffed out this way by Helo in Season 1, and again by Kendra Shaw in the movie. [[spoiler:Although five models exist as individuals without additional copies.]] Then again, their spines glow during sex, which begs the question of how Baltar never managed to noticed this about Six?
* The ''Series/{{Smallville}}'' version of Bizarro looks exactly like Clark unless he's weakened or, later, exposed to sunlight, in which case his face will briefly flicker into a broken-glass-ish looking form that calls to mind the earliest comic book versions of the character.
* ''Series/QuantumLeap'':
** A heroic example: Sam Beckett can be seen as he really is by the very young and animals, and sometimes by the insane, psychics, or people whose brain patterns are similar to his own. This also applies to his friend Al, who appears as a hologram that is normally invisible to others than Sam. Although due to real-life technical limitations, Al's hologramatic appearance sometimes casts shadows, his cigar smoke is affected by wind, his cigar smoke is visible despite the established rule that only things Al touches can be seen, etc.
** In one episode, a police psychic was able to see the real Sam after a while, meaning she is either insane or the real deal.
* ''Franchise/{{Buffyverse}}'':
** Buffy is supposed to be able to sense vampires magically, but this seems to be one of the Slayer powers that just did not manage to cross over. She still figures out two or three vamps because their ''fashion sense'' stalls at the point of time they, the vampires, first died. Dated clothes trumps weirdo magic-sense. There are a lot of vampires for whom this wouldn't work. At all.
** Faith mentioned being able to tell if Angel was anywhere in a building, so it works pretty well for her. Apparently Buffy just has the sensitivity of a brick given the number of times vampires have been able to get right up to her (or on one occasion, ''make out with her'') without being detected.
** Some of the classic tropes also apply in the Buffyverse. Vampires, for example, [[MissingReflection don't cast reflections]] (prompting Willow to ask Angel at one time, "How do you shave?"). They also have a tendency to shift into their GameFace when emotional. Also, only children or people suffering from infections could see Der Kinderstod in the ''Buffy'' episode "Killed by Death".
** In the ''Buffy'' Season 4 episode "Superstar", Adam sees through Jonathan's spell while everyone else is fooled; it is implied that this is due to his cybernetic nature. Adam himself believed it to be psychological, believing his utter certainty in his own reason for existence kept his mind from being fooled.
** A vampire actually makes sure to keep all mirrors out of their surroundings to avoid this. Unfortunately for him, this, along with the heavy curtains and slightly suspicious behavior, causes Cordelia to figure out exactly what he is.
** Doyle tends to involuntarily morph to his demon form when he sneezes.
* The Rakshasa are featured in ''Series/KolchakTheNightStalker''. This variation could appear as someone its victim trusted and/or loved; it could be repelled by the Swastika, which was a sacred symbol long before Nazi Germany co-opted it. This version was the direct inspiration for the ''D&D'' version, being vulnerable to a blessed crossbow bolt.
* Sorcerers in ''Series/{{Merlin|2008}}'' are indistinguishable from "Muggles" until they cast a spell, when their eyes flash gold.
* ''Series/{{Supernatural}}'':
** Mainly the true reflection variant (such as the Changelings, or the Siren). Occasionally, they'll throw in the physical defect variant (the "flip-to-silver" eyes for the shapeshifters, a retractable layer of fangs for vampires.) But since most of the characters in the show ''hunt'' these nasties, they also have several tests, just in case. For starters, iron and [[HolyBurnsEvil holy water]] are pretty good indicators that a baddie is about.
** Bobby actually uses these tests on Dean after the latter [[spoiler: gets out of Hell]], just to make sure Dean is, in fact, Dean. Bobby, being a CrazyPrepared badass offers everyone he thinks ''might'' be a demon a shot of holy water, or, if he's certain, gives them a beer with holy water in it. He does this test to Sam in ''Born Under a Bad Sign'' [[spoiler: (he's possessed)]] and Ellen in ''All Hell Breaks Loose'' [[spoiler: she's not]].
** In "End of Days" Dean gets an EleventhHourSuperpower; given that he's hours from being dragged into Hell, he can now see a demon's NightmareFace even when they're possessing a human. [[spoiler:Lilith cleverly gets around this by possessing Ruby's host (kicking Ruby back to Hell in the process), since Dean can't tell the difference between one demonic face and another. By the time he ''does'' figure it out, it's too late.]]
** PlayedForLaughs in "Hammer of the Gods" when Dean walks past an open hotel room containing an elephant...WTF? He walks back for a second look and has an indignant fat black man close the door on him -- the fat man turns out to be the Hindu god Ganesh, whose natural form is an elephant.
* ''Series/StarTrekDeepSpaceNine'''s brand of Changelings, the Founders, are liquid beings that can perfectly mimic any object (though some, like Odo, can't get the faces right). In later years, the only way for the Federation to scope out a Founder is through blood tests, as any material drawn from a changeling reverts back to its own natural liquid state (that looks very different from blood). [[spoiler:[[SubvertedTrope Except they've found a way around that]]...]]
* ''Series/DoctorWho'':
** The idea that the Perception Filter shorts out when people are in danger actually can be nicely applied retroactively to ''Series/{{Torchwood}}'', which finally gives a good explanation as to why no-one ever fell down the hole left by the base's lift.
** A few psychic paper examples; it doesn't work on people who know about it, and the person using it can't let their mind wander, or else the message can change. Also, in season 3 the Doctor tries to use the paper on William Shakespeare and finds out geniuses see it as what it is: a blank piece of paper. It also doesn't work if the subject has [[TooDumbToFool an amazingly terrible imagination]], as seen in ''Flatline''. Additionally, if the lie is too big (like the Doctor claiming to be a mature and responsible adult), the paper will just show a bunch of wavy lines.
* MonsterOfTheWeek Primator from ''Series/MightyMorphinPowerRangers'' could assume the form of any of the Rangers. The [[AchillesHeel one weakness]] in this power is that seeing his reflection renders Primitor unable to maintain the altered shape. It should be noted that it doesn't always force him back into his original form. (In one instance it caused the helmet of his altered form to change color.)
* In the ''Series/TrueBlood'' season 4 opener, Sookie finds herself in the Fairy Realm, which looks like a beautiful garden filled with young, attractive people, all of whom are either faries or [[HalfHumanHybrids fairy/human hybrids]], like Sookie herself. After Sookie realizes that the "light fruit" is a trap for the hybrids (anyone who has tasted it can never return to the human world), she blasts the fairy queen with her light powers. Suddenly, the garden turns into a desolate landscape, and the fairies reveal their true appearance -- that of goblin-like creatures with sharp teeth, pointy ears, and claws. Apparently, the queen was the one who maintained the illusion of a paradise.
** Also, in a literal case of Glamour Failure, the vampiric "glamour" ability (akin to hypnosis) is completely ineffective on Sookie (what with her not being fully human and all).
* The supernatural beasties called Wesen in ''Series/{{Grimm}}'' reveal their GameFace when excited or caught off-guard (called "woging" on the show). Even then, ordinary people still perceive the human disguise; only the eponymous line of monster hunters can detect the Glamour Failure. That said, there are times when the Wesen can show their GameFace to normal people if they really try and push it. The major downfall is most tend to GoMadFromTheRevelation as their human mind cannot comprehend what they are seeing. Usually, when a Wesen meets with Nick, they think him just another human who doesn't know the truth about them. When they "wog," however, they seem to realize instantly Nick is a Grimm and often react in terror (as Grimms are considered boogeymen to them). The third season finale has Nick finally learning that to a Wesen, a Grimm's eyes turn black when they wog, revealing what they are. Trubel starts wearing sunglasses in order to conceal her being a Grimm from Wesen. Nick also wears sunglasses during Monroe and Rosalee's wedding, as the majority of the guests are Wesen, and no one wants to start a panic.
* ''Series/{{Highlander}}'': The buzz that one immortal felt from the presence of another nearby. PlayedForLaughs in the pilot, when Duncan gets a buzz, while Tess is riding him. He mentions feeling something, and she replies that he better be feeling something after all that effort on her part.
* Cole in ''Series/{{Tracker}}'' could sense the life force of another alien if they were close enough. Varied with hybrids, though, Mel was part Cirronian but though Cole seemed to have suspected, he couldn't pick up on her life force. Also could be impaired if he was too close to lodestone.
* In ''Series/TheOuterLimits1995'' episode "First Anniversary", two stranded female aliens [[YouCannotGraspTheTrueForm whose true form is beyond the ability of human senses and sensibilities]], decided to mimic humans to cope with their loneliness. By using their PsychicPowers / VoluntaryShapeshifting, they could make themselves look and act like any man's ideal woman. [[DeconstructedTrope Unfortunately, humans develop an immunity to their powers after a year of close contact]], and the men inevitably go insane when they realize their [[StarfishAliens wives' true nature]]. WordOfGod is that they are FishPeople (given the episode descriptions of aquatic people). By the end of the episode, "Ady's" glamour has stopped working on her "husband" whose last appearance in the episode is strapped to a gurney on the way to a mental hospital. In the final scene she already has her sights set on her ex's best friend and has already taken a new form to appeal to his tastes.
* ''Series/Space1999''. The episode "The Bringers of Wonder" has huge disgusting aliens who mentally project an image of humanity to fool the inhabitants of Moonbase Alpha. They can only be seen in their true forms by commander Koenig (who had been subjected to an experimental medical treatment) or by someone looking at video recordings of them or affected by "white noise" auditory anesthesia.
* On ''Series/SleepyHollow'' a pair of witches use magic to appear to be young and gorgeous to anyone looking on them. Having been keeping out of society for so long, the duo are unaware that cameras can show their true forms, a pair of white-haired old women in flashy outfits.
* Both Green and White Martians on ''Series/Supergirl2015'' begin to revert back to their true bodies in close proximity to open flames, or at least the body parts closest to the flame.
* In ''Series/IDreamOfJeannie'' genies can't be photographed.
* In ''{{Series/Ghosted}}'' Max Jennifer and Leroy Wright spend an episode on the trail of a Sumerian succubus who steals men's hearts (literally). She has the power to take the appearance of different women. But each form still carries the Sumerian characters for “smoke” and “heart” tattooed on her body.
* In the third season of ''Series/TheMagicians'', all magic is lost to the world. A major result is that people who have relied on illusion spells suddenly find their true forms revealed, everything from a gorgeous model exposed as plain and overweight to a "hunk" revealed in his centuries-old form.
** It goes for buildings too as when Alice comes to her parents' manor, a usually refined and gorgeous place, only to discover it's the messy clutter it's truly been.

[[folder:Myths & Religion]]
* OlderThanPrint: In Myth/JapaneseMythology, a {{Kitsune}}'s (fox's) human-disguise is often revealed because:
** A Kitsune cannot hide its real eyes in reflections.
** A young, inexperienced, drunk, or just plain careless kitsune may accidentally reveal its fox ears or tail(s); this seems to show up especially often in anime.
** Kitsune are said to be incapable of saying "moshi moshi" (they are supposed to have an incomplete grasp of the language; a kitsune would only say one "moshi," not two), which lead to the phrase being used as a greeting. It is still a typical way to answer the phone in Japan.
* Also from Japanese myth, the Hone-onna (literally "[[DemBones Bone Woman]]") creates a look of a beautiful woman, based on how she looked when she was alive, to [[TheVamp get close to her chosen lover]] and [[LifeDrain drain him of life]] so they can be together forever. The problem is it only works on him and everyone else sees a man [[{{Squick}} flirting and caressing a rotting corpse]].
* Myth/NorseMythology:
** Odin gave up one of his eyes for wisdom. He usually is unable to fully conceal this.
* In Jewish, Russian, and some other folktale traditions, demons and vampires had bird feet which they couldn't conceal no matter what form they took.
* There is a story about the Welsh Saint Collen who entered a fairy castle at the behest of its king. He was invited to a banquet there, but wisely refused to eat, remarking that the food was only tree leaves. When the king asked what he thought of the red and blue garments worn by the castle servants, Collen said that the red signified the side being burnt and the blue signified the side being frozen. He then poured holy water on the ground, causing the castle to vanish.
* In Swedish folklore, trolls, sorcerers and the Devil can ''förvända synen'' -- "warp the sight" -- in onlookers. While there are some standard folkloric methods of protection, two bear mentioning. First, in many legends it is a active process. If the supernatural being isn't aware of you, you can see their true shape. For instance, there is a common story of a sorcerer who is heckled by a young woman. He threatens her and says he can call the river to raise up, and indeed a flood appears, so the woman jumps on a rock and lift her skirts. Another woman who comes by unseen by the sorcerer, however, see her jumping the rock and showing her unmentionables -- there is no flood. Second, some beings with glamour are trapped by their own vanity. Trolls, for instance, usually appear incredibly beautiful and dressed in expensive clothing, looking like refined ladies or gentlemen. Which seems useful, but the natural habitat of trolls is empty wilderness, preferably in the middle of the night, [[EerilyOutOfPlaceObject where rich gentlemen and fine young ladies don't wander around willy-nilly]].
* According to some Arabic folklore, [[OurGhoulsAreCreepier Ghouls]] can change form except for their telltale hooves.
* Gods in Myth/HinduMythology are said to be distinguishable from humans because they do not blink or sweat, the flowers on their garlands do not wither, and they hover slightly off the ground.
* In some versions, mermaids who took human form could always be identified because the hem of their dresses would always be wet, no matter how hot the day was or how long they were in human form.

[[folder:Tabletop Games]]
* In ''TabletopGame/ChangelingTheLost'', the Mask that disguises changelings as mortals always shows some small hint of their true nature and appearance. This gets worse as they become more powerful -- the most powerful, although still human in appearance, look decidedly ''off'', and are unlikely to be able to go anywhere without drawing unwanted attention. Also, certain people can sometimes see through the Mask -- the insane, those who are high, [[TomatoInTheMirror fetches]], very young children, people with certain forms of brain damage... it's not a sure thing, though. Furthermore, a changeling's shadow '''always''' shows hints of their true nature -- if you were turned into a mountain goat, your shadow's going to show horns, even if you strengthen the Mask to the point that even other Changelings can't see through it, or use Contracts (Fae magic) to appear as something or someone else entirely. Fortunately, the shadow only looks 'off' to other fae or creatures that can see through the Mask, not to everyone in general.
** In ''TabletopGame/PrometheanTheCreated'', Prometheans appear human, but other people can sense that there's something ''wrong'' about them on a deep, fundamental level. This feeling can build over time until the point where a [[TorchesAndPitchforks lynch mob is forming]]. It gets worse when a Promethean uses their innate powers around another person, because then the glamour fails utterly and they can see the Promethean in their true form - an animated corpse.
** Vampires in ''TabletopGame/VampireTheRequiem'' typically leave blurry images in mirrors, photos, and films though they can usually make the image look normal by focusing their will. The Hollow Mekhet [[MissingReflection can't be recorded and don't show up in mirrors at all]], because their [[EnemyWithout reflections are off somewhere making trouble]]. Also, vampires with low [[KarmaMeter Humanity]] slowly slide into the UncannyValley as they forget how to look alive.
** In ''TabletopGame/HunterTheVigil'', most Conspiracies have equipment or abilities that let their operatives pierce the various illusions and disguises used by the supernaturals, frequently while also indicating werewolves and other shapeshifters in human form as being non-human.
** Particularly bad for Geniuses in the fanmade ''TabletopGame/GeniusTheTransgression'': If a regular human so much as touches one of your wonders, reality itself will realize it's not supposed to work, and the machine will promptly go utterly berserk. If the mere mortal in question is just checking out your notes, or listening to you speaking at length about your research, they'll see/hear oodles of pseudo-scientific bullshit, though thankfully this won't cause much of a problem other than not being exactly endearing.
* ''TabletopGame/DungeonsAndDragons'' has the ''True Seeing'' spell, which penetrates all supernatural illusions and reveals the true forms of shapeshifted beings. Non-spellcasters have to rely on careful observation:
** The tiger-like Rakshasa in are demonic shapeshifters (derived from Indian folklore) who can disguise themselves as any humanoid creature, with the caveat that their hands are always facing the wrong way on their wrists. This has varied over the years from the hands being upside down to the palms facing outward. Another version from the spinoff parody ''Dungeon Hack'' described their hands as being upsidedown and switched, so that the palms faced inward, but the thumbs were on the bottom and the pinkies on top. This is the only version where the palms faced inward.
** The "Changelings" are a sort of doppleganger/human hybrid who can appear like any sort of humanoid they wish, within size and mass limitations. [[ThisWasHisTrueForm They turn back when killed]], and their young are unable to maintain their disguises while asleep. Their true forms are grey, with gangly and slightly off proportion limbs, white eyes, and only the slightest indication of a nose and mouth. An article on Changelings in one ''TabletopGame/{{Eberron}}'' sourcebook dedicated a section to "ways to spot a Changeling". The top causes of Glamour Failure are [[OohMeAccentsSlipping an incorrect accent]], incorrect clothing (the body might transform, but the clothes do not) and a lack of knowledge on local customs.
** While vampires of ''TabletopGame/DungeonsAndDragons'' appear mostly as they did in life, they are easily distinguishable by their lack of shadows and reflections.
** Many illusion spells can be foiled if the sensory input is inconsistent, like if someone's hand feels scaly despite looking like ordinary skin.
* ''TabletopGame/{{Exalted}}'':
** The Lunar Exalted are shapeshifters extraordinaire, but each one possesses a single animal feature -- its Tell -- that remains consistent regardless of what form it takes. The Tell is usually fairly subtle, such as an oddly-colored patch of hair or strange-looking eyes, but it does allow anyone who knows what he's looking for to identify the Lunar.
** Solars have an awareness charm that make them ignore glamour as if it were not there.
* Many of the Glamour Failures in ''TabletopGame/{{Deadlands}}'' are exactly what one would expect from a series were AllMythsAreTrue: silver repels even human-form werewolves, and so on. The series' most unique form of [[CameBackWrong revenant]], the Harrowed, bear most extensive discussion: they carry the [[EvilSmellsBad smell of death]] everywhere they go, have a distinctly [[EvilAlbino pale complexion]], keep a [[RedRightHand scar from their cause of death]], can potentially [[InhumanHuman be rotting and decayed]], and are prone to [[EvilDetectingDog setting off nearby wildlife]]. If a lot of their giveaways make them sound like evil incarnate, it's worth remembering that even the [[AntiHero nice]] [[HeroicWillpower ones]] have a JekyllAndHyde complex.
* In the ''TabletopGame/{{Shadowrun}}'' universe, mages have to learn and cast a more difficult (reflected in drain rating) version of illusions if they wish them to fool electronic sensors too. (Cybereyes don't count because they are bought by the owner's essence.)
* ''TabletopGame/{{Nobilis}}'':
** For the weirder Powers, Afflictions that reveal something about your supernatural status fall under this category. You get Miracle Points whenever, say, your reflection burning like a phoenix or your shadow running off to buy USB drives or whatever it is causes serious problems for you. Also, Lord Entropy's RedRightHand -- his palms constantly dripping with blood -- remains constant no matter what form he takes.
** The [[HumanoidAbomination Excrucians]] also have a universal one other than their [[InhumanlyBeautifulRace utter beauty]]-their eyes [[BlackEyesOfEvil are like windows to the night sky]], and the stars are falling.
* ''TabletopGame/Warhammer40000'': The Dark Eldar use strange technology to appear youthful and [[EvilIsSexy sexy]] to the majority of beings, but it doesn't work on [[PsychicPowers psykers]] and [[OurDemonsAreDifferent daemons]]. To them, the Dark Eldar appear in their true forms, as hideous, rotting corpse-like monsters.
* Many of the Neverborn in ''TabletopGame/{{Malifaux}}'' appear human, and while some have eyes or skin that are somehow "off," others only have their true nature revealed when someone tries to draw or photograph them.

* In the first DreamSequence of ''Theatre/LadyInTheDark'', Liza Elliott dreams of herself as a wealthy, glamorous lady in blue. As in her dream she is a renowned celebrity with legions of admirers, she can hardly refuse to allow her portrait to be painted. When the portrait is unveiled, it shows Liza as the austerely dressed, neurotic magazine editor she really is. Consternation ensues.

[[folder:Video Games]]
* In ''VideoGame/TheLegendOfZeldaALinkToThePast'', you find a girl trapped in one of the dungeons who asks you to lead her out, but if you do so she tells you not to go out that way. You have to lead the "girl" into a room with bright sunlight coming in, which reveals her to be the boss Blind. Which makes it very odd that, when you first rescued her from the dungeon, she asked "Please, take me outside."
* In ''VideoGame/PhantasyStarOnline'', in the Seabed area, there are robot enemies that are usually invisible. However, you can see their reflections in the water and reflective surfaces that are usually common throughout the area, making it possible to attack them. Also, using a lightning spell will short out the invisibility for some time.
* In the ''VideoGame/KingdomHearts'' series, the screen tends to fill with TV static when [[spoiler: artificially-made memories start to fail]].
* In ''VideoGame/TheSimpsonsBartVsTheSpaceMutants'', Bart Simpson can see through the aliens' disguises with X-ray specs.
* In ''VideoGame/SuperMarioRPG: Legend of the Seven Stars'', the fake residents of Seaside Town look sort of like real mushroom people, except they have metallic colors and don't move like a normal mushroom person should.
** In ''VideoGame/PaperMario64'', the Koopa Bros. attempts to block off the Toad Town gate via apparently magical Toad disguise fails because their hats are black and they pretty much try to be conspicuous.
** ''Paper Mario'' also had an instance where Peach magically disguised herself as one of Bowser's {{Mook}}s in order to sneak around the castle. The reason [[TheDragon Kammy Koopa]] was able to figure out the deception? Peach ''[[TheNoseKnows smelled too nice]]''.
* In ''Franchise/DevilMayCry'', when Dante and Vergil's father Sparda took human form, his shadow remained shaped like a demon.
* ''VideoGame/{{Bayonetta}}'' features a similar example to ''[[Franchise/DevilMayCry DMC]]'' in that her physical form is always the normal but her cast shadow will display her butterfly wings that she uses to double-jump.
* Spies in ''VideoGame/TeamFortress2'' have both an invisibility watch and a disguise kit. The invisibility will flicker if the spy is shot or if someone runs into them, and the disguise will fail if they use their gun or knife. If an enemy pyro lights a spy on fire, the disguise and cloak are maintained, but they are completely worthless as friendly players cannot be lit on fire, and the player is clearly a spy once they're on fire. Plus, ya know, the whole "burning to death" thing.
** The cloak will actually fizzle out if a Spy gets covered in Jarate (the Sniper drinks way too much coffee) or Mad Milk (whatever is in that jar the Scout's holding, it isn't milk). A disguise won't vanish, but since Jarate and Mad Milk don't affect allies unless they're on fire, and since they'll [[UrineTrouble cry out when they get hit]]...
* In ''VideoGame/BlazBlue'', when [[spoiler: Captain Hazama ]]makes his appearance at the end of the game, he becomes so animated and overjoyed about his victory, that he reveals himself to be [[spoiler: Yuuki Terumi, an immortal, nigh-unkillable psychopath]]. Perhaps the only example of a Villain's glamour failing due to sheer enthusiasm.
** Anytime in the sequels when he get overly excited about his villainous plans, he exhibits features such as glowing eyes, an inhumanly-wide grin and hair standing straight up.
** In [[VideoGame/BlazblueChronophantasma Chronophantasma]], when Relius uses his Astral Heat on Terumi, Relius has him bound to a chair with a mirror behind him, revealing Terumi's true form.
* Next time you fight a {{demon|icSpiders}} in ''VideoGame/GodHand'', take a look at the other {{mook}}s around you. They all gain GlowingEyesOfDoom.
* In TheVeryDefinitelyFinalDungeon of ''VideoGame/MetroidPrime3Corruption'', Samus' ship refuses to let her back in because the ToxicPhlebotinum has overwritten her DNA to the point that she isn't even classifiable as a HalfHumanHybrid anymore.
* There's a point in ''VideoGame/{{Okami}}'' where you must encounter a creepy old couple. Pull them into the moonlight and their shadows reveal that they're demons. Though due to their creepy and somewhat disturbing demeanor, it's not that much of a surprise when they reveal themselves. In fact, it makes more sense.
* Scotia in ''VideoGame/LandsOfLore: The Throne of Chaos'' possesses a magical ring that allows her to take any form she wants. The only thing she can't disguise is her eyes, which are always yellow. On several occasions, she uses this ability to try and trick the player.
* In ''VideoGame/HeroinesQuest'', you can find out that [[spoiler:the villager Regin]] is a svartalf, because his eyes are inhuman.
* The ''TabletopGame/DungeonsAndDragons''-based BeatEmUp ''Tower of Doom'' has a Displacer Beast as the boss of Fort Cruth. It does the species's traditional projecting-a-false-image... but a guard you meet just before the battle notes, "Why would two beasts only cast one shadow?" Indeed, the real one is the one with the shadow.
* ''Franchise/TheElderScrolls''
** For many of Tamriel's [[OurVampiresAreDifferent vampire]] bloodlines, the longer they go without feeding, the more monstrous in appearance they become. Eventually, they will no longer be able to pass as mortal and risk being attacked on sight. Series' lore tells of the Bonsamu bloodline of Valenwood, who are ''completely'' indistinguishable from mortals unless seen in the light of a candle.
** In ''[[VideoGame/TheElderScrollSIIIMorrowind Morrowind]]'', Vvardenfell's strain of vampirism brings instant monstrous changes regardless of feeding. There is no hiding the fact that one is a vampire, which means being cast out from civilized society. Given the influence of the [[CorruptChurch Tribunal Temple]], which considers vampires to be nothing more than monsters to be killed on sight, this forces vampires to retreat into remote wilderness areas and abandoned ruins where they form their own clan societies.
** In ''[[VideoGame/TheElderScrollsIVOblivion Oblivion]]'', Cyrodiil's strain of vampirism allows vampires to seamlessly blend in with mortals as long as they feed regularly. They are also known to be able to control their blood lust to a far greater degree than other bloodlines, rarely killing their victims outright. They are typically well-placed in Cyrodiilic society, able to manipulate local politics to their benefit.
** ''[[VideoGame/TheElderScrollsVSkyrim Skyrim]]'':
*** Similar to ''Oblivion'', The more a vampire feeds, the less powerful they are but also the more normal looking they appear. If the player becomes one, going one or two days without feeding and people start noticing odd things like how pale your skin is or your creepy eyes. On day three you suffer catastrophic glamour failure and most [=NPCs=] will turn hostile.
*** With the ''Dawnguard'' DLC, this penalty is removed and [=NPCs=] no longer grab their TorchesAndPitchforks to chase you out of town. However, it's said that ''everyone'' is completely terrified of you, for reasons they can't exactly pinpoint. ''Dawnguard'' also redesigns Vampires so they now possess GlowingEyes. While logically this ''should'' immediately out a vampire away, it is implied that only the Dragonborn [[InvisibleToNormals can notice this]], due to possessing a unique [[OurAngelsAreDifferent Aedric soul]].
*** Werewolf players also have minor glamour failures according to guard banter, wondering did they just see fur growing out of your ears, ask if you've been tending hounds because you stink of dog, as well as noticing your disturbing [[PsychoticSmirk wolvish grin]].
* In ''Franchise/{{Pokemon}}'', Zorua and Zoroark can be sent out disguised as another Pokemon. However, it cannot use moves other than its own, so you can often tell it's a glamor (although it could be a hack as well). Also, it reverts if it takes a hit.
** A less obvious tell is that it's a pure Dark Type, meaning it's immune to psychic. Using a psychic move will be ineffective, but most players end up wondering why it didn't work, at least until the next turn. It doesn't even revert. Also, because it's only ever Dark type, if it shows vulnerability to something the Pokemon it is disguised as shouldn't be affected by, such as a Flying type Pokemon to spikes, it gives itself away.
** Another situational tell is that the two will only have their own ability, not the ability of the Pokemon they're disguised as. Some Pokemon have abilities that immediately alert the opponent or take effect immediately when sent. The lack of this event reveals the Pokemon as Zorua or Zoruark.
* Surprisingly an InvertedTrope in ''VideoGame/TheLegendOfZeldaTheWindWaker''. On a NewGamePlus, Link's Grandmother, instead of giving him the iconic green hero's clothes, gives him what's either invisible clothes, or absolutely nothing. Link wears them over his normal clothes, with absolutely no difference. It seems at first that she's just playing a joke on him, but looking at Link's shadow reveals the indistinctive shape of his floppy hat. This may also be a programming oversight, however. According to his grandma, they're magical clothes that are only visible to honest people. ''"What's the matter? You see them, don't you?"''
* ''VideoGame/TheDarknessII'': The asylum intermissions are so painstakingly detailed, you'll have a hard time wondering if (A) the Darkness is screwing with Jackie into unwittingly giving up his soul or (B) the video game version of Jackie really is a demented lunatic who thinks he's Jackie Escacado from reading too many The Darkness comic books. Then you find out that the asylum is ''showing Lovecraft movies as relaxation therapy''. Hilariously stupid, aren't they?
* Glamour spells are a plot point in VideoGame/TheWolfAmongUs, starting with episode 2 because [[spoiler: they're expensive and constantly in demand so Aunty Greenleaf is selling cheap knockoffs that are prone to showing an increasingly imperfect disguise and failing.]]
** Played with. GL's version of a glamour capsule is more "different" than a failure; there are a lot of "tells" in this version, but it never fails until the capsule is opened. [[spoiler:Until the easily portable glamour capsule is ripped apart, nobody realizes that the dead Snow White body double is a giant, fat troll! The body double WHOSE HEAD WAS RIPPED OFF.]] In fact, it's so good that [[spoiler:Bigby suddenly realizes that there is a possibility that either A)Faith is alive and Nerissa is dead or B)Nerissa used a glamour to look like Faith when they first met - while Bigby and Woody were throwing sinks]]. [[SarcasmMode Yeah, sure, that just screams failure doesn't it]]?
** The [[AllThereInTheManual Book of Fables]] makes it very clear why knockoffs are bad compared to the more effective, legitimate versions sold by the Witches of the 13th Floor - interacting with other Fables won't put stress on the spell but [[{{Muggles}} Mundies]] would. It would show {{Glamour Failure}}s more often, leading to Mundies to question the nature of those under it before the Glamour is broken completely. All glamours have this flaw which is why Fables don't interact with them much but GL's glamours, being Mass-Produced and with less quality, are far more prone to failure than anyone else's.
* The G-Man from ''VideoGame/HalfLife'' is able to disguise himself as a human from a visual standpoint, but his speech -- which is peppered with AccentUponTheWrongSyllable, words pronounced too quickly or slowly, no pausing between sentences, etc. -- is quite uncanny, to say the least.
* In ''VideoGame/DarkSouls'', you can [[DressingAsTheEnemy disguise yourself as the Silver and Black Knight]] to fool the PVP invaders. The problems are, not only you are not as tall as the real ones, the way how you wield their weapons is different from the real counterparts. The dead giveaway, however, is that invaders can lock onto you.
* In ''VideoGame/DarkSoulsII'', [[ProfessionalKiller Maldron The Assassin]] poses a HeelFaceMole to fool you in your second encounter (The first encounter had him being outright hostile). The problem is, while he looked like a White Phantom, there is no message of Phantom summoning because he is now a non-phantom enemy. And you can target him just like other enemies. It doesn't stop the PVP invaders from using him as a TokenEvilTeammate and pull a DopplegangerAttack together, however.
* In ''VideoGame/DarkSoulsIII'', you can repeat this feat and disguise yourself as Fire Witches, Lothric Knights and all kind of armored humanoid enemies. You can even disguise yourself as a hollow. However, unlike the the two previous instalments, not only your character name is not shown in the phantom name list for the host, your name is ''highlighted in red'' from a distance if you are a Dark Spirit. It doesn't even take any effort to dig you out from a crowd of enemies.

[[folder:Web Animation]]
* At the very end of the pilot of ''WebAnimation/BeeAndPuppycat'' Puppycat's reflection in a window briefly changes to show [[spoiler:the outlaw in a story Puppycat told earlier]].
* You thought Whites were unsettling with their frozen smiles in ''WebAnimation/LuckyDayForever''? [[spoiler:Wait until you see [[http://i1077.photobucket.com/albums/w474/CirnoCultist/white_zpscsykiduu.png what lurks beneath the surface]].]]
* ''WebAnimation/MysterySkullsAnimated'': Lewis, a ghost, ''can'' appear as he did in life... but there's always something wrong with his eyes when he does. They appear as either HiddenEyes, or as black pits with brightly glowing irises.

[[folder:Web Comics]]
* The protagonist of ''[[http://www.magickitsune.com Fox Tails]]'', Keen Kotaru, possesses a so-far unexplained ability to see through the Glamours of the various animal-spirits that are otherwise maintaining a {{Masquerade}} in our world. His ability to thus notice the remaining animal features of transformed spirits is what drives the plot, and allows him to effectively fight the evil spirits...
* In ''Webcomic/ErrantStory'', the Elven Rangers who move around the world of men in search of 'Errants' (half-elves who frequently become psychotic) often uses glamours to disguise their elven nature. At one point, however, a young child can see through it, though [[NotNowKiddo her mother dismisses it]]...
* In ''Webcomic/DanAndMabsFurryAdventures'', the Cubi all possess powerful shape-shifting abilities, which obviously comes in handy [[HornyDevils for many things]]. However, they all have a single "marking" on them that they cannot change -- and which also shows what clan they belong to. If you manage to spot such a mark, and happen to know what they mean, you'll both know that you're actually facing a Cubi -- and ''usually'' whether it's the kind that feasts on pain, terror and suffering, or the kind that feeds on lust, joy and happiness. Very handy for determining what your next response should be, really. Although make-up or clothing can conceal them, but only real clothing, not clothing made by shapeshifting.
* In ''Webcomic/GunnerkriggCourt'', certain individuals are living Glamour Failure, who unconsciously dispel illusions by their very presence. Antimony is one such person, as her encounter with the ghost in the hospital showed. Ironically, this can work against her. During the trip to the afterlife bureaucracy in [[http://www.gunnerkrigg.com/?p=1296 chapter 46]], Kat has such a logical perspective that everything she sees looks like a Halloween house, while Antimony and Mort can see the afterlife in all its magnificent glory. Regardless of who has the "real" perspective, Kat's perspective allows her to flip off an old man in a horror costume, while Antimony and Mort see said old man as a [[EldritchAbomination GIANT PERSONIFICATION OF RAINBOW SKELETAL CENTIPEDE DEATH]]. He even leaves his room because Kat ordered him to!
* ''Webcomic/LastRes0rt'' uses the "Dead Eyes" of the Djinn-si as a quick tell-tale for identifying most Dead Inside, and it's also the only part of Alice's body that can't be changed by shapeshifting. For [[OurVampiresAreDifferent Vampire Djinn-si]], though, it's just part of their GameFace (though if you piss one off enough, you can still cause an AccidentalReveal).
* Shannon in ''Webcomic/BloodyUrban'' retains yellowish eyes and green-tinted skin while shapeshifted into different forms.
* [[http://headtripcomics.comicgenesis.com/d/20060622.html A very subtle one]] in ''Webcomic/HeadTrip''. Look at the teacher's shadow on the chalkboard.
* In ''Webcomic/TalesOfTheQuestor'', the illusions of the Fae can be pierced by someone born with "the second Sight..." or by someone with the latent ability who daubs their eyes with elderflower balm or drinks elderberry wine.
* In ''Webcomic/ElGoonishShive'' any Greater [[HybridMonster Chimera]] has antennae that [[http://www.egscomics.com/?date=2011-07-27 normally remain in all their forms]]. Until one uses a [[TransformationTrinket Cosmetic Morph Device]] mass-produced by their common parent species. Though in human form these look like [[PrehensileHair prehensile thick locks]] easily disguised [[http://www.egscomics.com/?date=2002-03-03 in long normal hair]] -- unless they happen to grow on a hairless part of the head, but that's a rare anomaly.
* In ''Webcomic/RustyAndCo'', Mimic's lips are always visible, regardless of his form.
* In ''Webcomic/{{Erstwhile}}'', [[http://www.erstwhiletales.com/brothersister-24/#.UI84NGdHGuI the stepsister in "Brother and Sister" is missing an eye, and not even her mother's magic can hide that.]]
* In ''Webcomic/{{Godslave}}'', Sobek's crocodile teeth start to show when he gets emotional, and sometimes his reflection is of his true form rather than that of the man he pretends to be.
* ''Webcomic/AwfulHospital'': Any Zone presents AFormYouAreComfortableWith for beings within, even ones as distantly removed as a human and a fungus, to interact; enough of a shock causes the façade to crack.
* At least one of the changelings in ''Webcomic/CharbyTheVampirate'' gets [[http://www.charbythevampirate.com/comic/1078 the eyes]] wrong when [[KillAndReplace taking on someone's form]] and all changelings retain their hair spikes.
* In ''Webcomic/LeagueOfSuperRedundantHeroes'', an alien infiltrator attempts to blend in with a PerceptionFilter making it appear like an elementary school girl... but [[http://superredundant.com/?comic=756-secret-invasion still leaves the tracks of a creature the size and weight of a bipedal rhino]].

[[folder:Web Original]]
* ''Wiki/SCPFoundation'', [[http://scp-wiki.net/scp-870 SCP-870 ("The Maybe There Monsters")]]. The creatures known as SCP-870 can only be seen by people with schizophrenia. Each schizophrenic person who looks at a SCP-870 sees something different (a spider with too many legs, a giant ant with a human face, etc.).
* The webnovel ''Literature/JohnDiesAtTheEnd'' tells the story of two college dropouts who discover and fight an otherworldly invasion after a chance run-in with a supernatural drug changes their perceptions forever. As a result, they see a lot of freaky stuff [[InvisibleToNormals invisible to everyone else]], but they also gain a lot of experience identifying subtle clues that ordinary people could notice if they paid attention. They learn mirrors can be used to circumvent certain illusions, religious symbols can be used to flush out and ward off evil, and household pets can be used to detect and identify paranormal beings.
* The original imagining of [[Franchise/TheSlenderManMythos Slender Man]] had a face which appeared different to each person looking at him, and appeared faceless on cameras due to Glamour Failure. This facelessness eventually became one of his defining characteristics, so now he's simply TheBlank to everyone who sees him.
* The French supervillain Mindscape, from the ''Roleplay/GlobalGuardiansPBEMUniverse'', avoids cameras as often as he can, because anyone viewing him on film or in photographs can instantly tell he's a deformed hunchback and not the GQ-quality supermodel-handsome man he uses his powers of illusion to pretend to be.
* In ''Podcast/WelcomeToNightVale'' the cat(?) Khoshekh which hovers immobile in the radio station bathroom doesn't show up in photographs. Also, the person who took the photograph dies horribly. Khoshekh also has poisonous spine ridges, a tendril hub, and venomous fangs, raising questions over what kind of cat Khoshekh is or, alternately, what kind of thing the residents of Night Vale call cats.

[[folder:Western Animation]]
* ''WesternAnimation/BatmanBeyond'': Whenever Derek Powers gets angry, which is frequently, his powers flare up and start to burn through his artificial skin, revealing that of the [[ILoveNuclearPower radioactive]], [[PowerGlows glowing]] villain Blight. Actively using his powers for even a few seconds will completely shatter it, requiring him to have new skin grafted on. His inability to keep his skin on through the events of any given workday actually makes him a case of BlessedWithSuck. This worsens as he undergoes a [[VillainousBreakdown figurative meltdown]], followed by a [[SuperPowerMeltdown literal meltdown]] which left him dead for good.
* In ''WesternAnimation/TheGrimAdventuresOfBillyAndMandy'', whenever Nergal Junior transformed, he always retained his green eyes, glasses, and fangs. The most notable Glamour Failure is when he tried to mimic Mandy. [[PerpetualFrowner The reason being that she never smiles.]]
* In ''WesternAnimation/SamuraiJack'', anything Aku transforms into has the same black/green/red color scheme he does, and his true form shows up in reflections. He managed to disguise himself as a beautiful woman and fooled Jack in one episode, after which Jack stayed alert; a second attempt at masquerade led to Aku being totally outmaneuvered.
* ''WesternAnimation/JusticeLeagueUnlimited'':
** While not a person, an episode has Hawkgirl discover a mine on a faraway planet was fake (and, thus, a trap) when the holographic shadows it cast from her [[PowerGlows glowing mace]] didn't follow the same direction of the other shadows the mace cast.
** Earlier, a spell cast on Franchise/{{Superman}} and Franchise/WonderWoman to make each think that the other is a demon can only be broken once they see the other's reflection. The problem is that, once Superman sees what is going on, he feels unable to fight Wonder Woman, and thus has to take a beating until Diana sees it too.
** And there is the whole "In Blackest Night" episode, where John is tried for destroying a planet. The others notice the planet's satellite is still orbiting it, find the holoprojector, and blast it apart, causing the planet to reappear right in front of the judges.
* In ''WesternAnimation/CodeLyoko'', [=XANAfied=] people and Polymorphic Specters can be recognized by their [[MindControlEyes pupils turning into]] [[HellishPupils "Eye of XANA" symbols]], or by their tendency of getting blurry with "static" from time to time. They can usually suppress this long enough to force a SpotTheImposter Check, though.
* ''WesternAnimation/XMenEvolution'':
** Kurt's image inducer. Given that it really only needs the settings "off" and "on" was there really the need to give it so many options and make the off button so incredibly easy to press by accident? As the image inducer only makes him LOOK human, anyone who touches him can still feel his fur. In the comics, he uses it at least once to trick a villain. It could've been a set-up for future writers that just never got used.
** Quicksilver has his moments too. It's implied that being super-fast is his natural state and that it takes an effort to slow down to human pace, and, as such, he speaks slightly faster than any other character and often can't restrain his powers over small distances; for example, in his first appearance, when he zooms around Evan in the locker room ''before'' revealing himself more dramatically later on.
* ''WesternAnimation/TheSimpsons'' episode "Bart Sells His Soul" features a number of these: automatic doors don't open for soulless Bart, he can't fog up glass with his breath, he can't laugh, his eyes briefly turn cat-like as he performs a HissBeforeFleeing, etc.
* ''WesternAnimation/TeenTitans'': Beast Boy retains his green color when changing into other animals. This would make infiltration difficult.
-->'''Beast Boy:''' Do I hear an undercover mission coming on, 'cause I'm a master of disguise!\\
'''[[DeadpanSnarker Raven]]:''' Yeah, a green mongoose is gonna blend right in.
* The Christmas special "The Story of the Leprechaun's Gold" had a situation where banshees could take human form, but were always identifiable by their banshee tears, which they could not hide.
* ''WesternAnimation/TomAndJerry'':
** "The Invisible Mouse" has a variation; when Jerry renders himself invisible with invisible ink, Tom at one point is able to locate him when he sees his shadow. [[FridgeLogic How an invisible body casts a shadow]] [[RuleOfFunny is never explained.]]
** Another episode with the same shtick had Jerry get coated in flour, thus rendering his invisibility useless.
* The memory-manipulating parasites in ''WesternAnimation/RickAndMorty'' are difficult to pick out, since they manufacture entire lifetimes-worth of memories into people, so you won't question why that nice uncle or Frankenstein Monster or Photography Velociraptor is staying at your place. This breaks down when Morty realizes that they can only manufacture ''good'' memories; he and his family can tell real friends and family from the wacky fantastical parasitic characters infesting the house because the family have all inflicted horrible experiences upon one another. Except [[spoiler: Mr. Poopy Butthole.]]
* ''WesternAnimation/MyLittlePonyFriendshipIsMagic'': In "To Where and Back Again", Chrysalis sees a brief reflection in Starlight Glimmer's eyes that tells her she's really Thorax in disguise.