You see that guy there? He's crawling around on all fours, and...is he sniffing that guy's butt? Who does he think he is?

A dog, of course.

There's plenty of ShapeShifting tropes, but this one is a bit different. You see, these characters don't actually change form, they just ''think'' they do. This is whenever a character believes he is a dog or any other animal without actually being it.

If faithful and well-behaved it might actually make a good HumanPet. AllAnimalsAreDogs might be explained if other non-dog animals are under the same delusion. Do not confuse with [[AGodAmI Delusion of Godhood]], which is something else.
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!!Examples:

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[[folder: Anime & Manga ]]

* The episode of ''Anime/{{Pokemon}}'' where a bunch of kids get accidentally hypnotized by a Hypno into thinking they're Pokémon.
** There's also one where Ash gets hypnotized into thinking he's a Bulbasaur.
* ''Anime/PrincessMononoke'''s San, who adamantly believes she's a wolf and even wears a wolf pelt to look the part. Justified, since she was literally RaisedByWolves after [[spoiler:her birth parents were caught intruding in Morro's forest and abandoned San, when she was an infant, to save themselves.]]
* ''Manga/SketDance'': Distracted by a cat while hypnotizing himself, Tsubaki started acting like a cat. [[BrainwashResidue It took some time before he stopped meowing.]]
* Ranma from ''Manga/RanmaOneHalf'' has an extreme fear of cats. If he is isolated with a cat in a very small space, or when he can no longer cope with his fear of cats, he begins behaving like a cat himself and becomes a master of the "Cat Fu".
* Shokora in little-known anime ''Anime/{{Massugu ni Ikou}}'' is a dog who believes himself to be a human. He's eventually convinced by the other dogs that this can't possibly be the case... so by the next time they meet him, he's switched to believing that he's a ''cat'' instead.
* Kaori Yuuzaki does this in ''Manga/TheWorldGodOnlyKnows'', sniffing to find the scent of a perfume she tagged someone with earlier. However, considering [[AxeCrazy her personality]], in context it is ''creepy as hell''.
* In ''LightNovel/OreNoNounaiSentakushiGaGakuenLoveComeOZenryokuDeJamaShiteiru'', Chocolat acts like a dog at times. She instantly obeys orders to "fetch", "shake", "sit", etc.

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[[folder: Comic Books ]]

* In ''NewMutants'', Catseye of the [[EvilCounterpart Hellions]] thought she was an actual cat.
* In ''ComicBook/{{X-Men}}'', the Xavier Institute once had a student named Overlay, whose power was that he could induce this.

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[[folder: Film ]]

* Big part of ''TheAnimal''.
* The framing joke in ''Film/AnnieHall'' is about someone like this.
--> I thought of that old joke, y'know, the, this... this guy goes to a psychiatrist and says, "Doc, uh, my brother's crazy; he thinks he's a chicken." And, uh, the doctor says, "Well, why don't you turn him in?" The guy says, "I would, but I need the eggs."
* This is the overall theme of the early NicolasCage movie ''{{Birdy}}'', in which Cage's friend believes he's a bird after nearly being killed at war.
* The forgettable French comedy movie ''{{Didier}}'' is about a dog that's somehow turned into a human, but keeps a dog mind and HilarityEnsues.
* In ''Film/HighAnxiety'', there's a mental patient who thinks he's a cocker spaniel.
* In ''Film/TheKiller'', near the closing shootout of the movie, a dying Fung Sei tells Ah Jong that he doesn't know whether he's a human or a dog anymore, which may be a sign that he's close to (or has already crossed) the DespairEventHorizon as a result of the monstrously cruel NoHoldsBarredBeatdown he received at the hands of Wong Hoi, who repeatedly likened poor Sei to a dog during the beating.
* ''Creator/MontyPython'': the Silly Olympics includes the [[http://www.youtube.com/watch?v=jjm_IdLCWc4#t=2m01s 3,000 Meter Steeplechase for People who Think They're Chickens]].
* This was a subplot in ''TheTraceyFragments''. Like, she'd hypnotized her brother into thinking he was a dog, permanently or something. I'm too tired right now to double check that.
* ''Film/WildWildWest''. Artemus Gordon uses a spinning spiral disc to hyponotize General "Bloodbath" [=McGrath=]. He tells [=McGrath=] that he'll be Gordon's "little doggy" and commands him to speak. [=McGrath=] makes dog sounds, and Gordon tells him to speak in words. [=McGrath=] starts growling angrily and Gordon notices that his disc has stopped spinning. [=McGrath=] then attacks Gordon while growling and snarling at him.
* The Disney film ''You Lucky Dog'' has a dog psychic played by [[GrowingPains Kirk Cameron]] who ends up inadvertently chanelling the personality of a rich man's St. Bernard whenever he gets excited.
* In the sequel of the live-action ''Disney/OneHundredAndOneDalmatians'', there is a parrot who thinks he's a dog.
* In ''Film/TheThreeStooges'' short "From Nurse to Worse", when Curly feigns insanity in order to defraud an insurance company, his apparent madness takes this form. Things get a bit out of hand when he bites the doctor examining him.

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[[folder: Jokes. ]]

* At least one joke goes something like this:
-->Two cows are grazing in a field. First cow turns to the second and goes, "You hear about that Mad Cow Disease that's been going around?". Second cow looks over and says, "Yup, makes me glad I'm a penguin.".
* Of course there's the classic:
-->'''Man:''' Doctor, you gotta help me. My son thinks he's a chicken!
-->'''Doctor:''' Why did you take so long to tell me?
-->'''Man:''' I needed the eggs.
* Another involves a man who keeps thinking he's a dog going to see a psychiatrist. Upon being told to lie down on the couch, he objects: "Oh no doc, I'm not allowed on the furniture".

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[[folder: Literature ]]

* King Nebuchadnezzar from ''Literature/TheBible''.
* In ''Literature/{{Discworld}}'' books this is a speciality of witch Granny Weatherwax.
->''"Despite many threats, Granny Weatherwax had never turned anyone into a frog. The way she saw it, there was a technically less cruel but cheaper and much more satisfying thing you could do. You could leave them human and make them think they were a frog, which also provided much innocent entertainment for passers-by."''
-->'''Magrat:''' "I always felt sorry for Mr Wilkins...It was so sad watching him try to catch flies on his tongue."
* ''The Wee Free Men'' also has a toad who wonders if he's a man turned into a toad or a toad cursed into believing it. [[spoiler:The former]] is true.
** Inverted in ''Discworld/WitchesAbroad'', where [[BigBad Lady Lilith]] has given a wolf human thoughts to make the Little Red Riding Hood story come true. This drives the wolf mad, and he allows the woodcutter to cut off his head.
* Several characters in EdgarAllanPoe's "The Celebrated System of Doctor Tarr and Professor Fether".

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[[folder: Live-Action TV ]]

* Played with on ''Series/HowIMetYourMother'' when the others point out that Robin's new date is basically a dog. While he doesn't act like a dog, his behavior is reminiscent of one (running after a squirrel, chasing his "tail", etc).
* In ''Series/{{Misfits}}'', one person gains this as a superpower. They go through bouts of thinking they're a Jack Russel, but don't shapeshift.
* In one episode of ''ThirdRockFromTheSun'' Harry's pet from back on the homeworld tracks him down on Earth; the pet is transformed into a human (BillIrwin) but acts like a dog.
-->'''Tommy:''' Oh, good. [[SarcasmMode This'll help us be less conspicuous]].
::They cover by saying he [[TakingTheBullet took a bullet]] to the brain for Harry in "that war."
* On one episode of ''SmallWonder'' Vicki hypnotized several people to act strangely, including making one man think he was a dog to the point that he almost relieved himself on a fire hydrant.
* Invoked in an episode of ''RemingtonSteele''; they need access to a woman in a mental ward, so Steele pretends to be this to get in.
* The ''Series/HorribleHistories'' potrayals of George III usually have him thinking he's a kangaroo.
* In an episode ''Series/{{Roy}}'', Roy (who is a living cartoon) gets a blow on the head while pretending to be a dog and starts believing that he is actually a dog, to the point of growing a tail and dog ears.
* In the ''Series/{{Supernatural}}'' episode "Dog Dean Arternoon", the potion Dean takes in order to communicate with a canine witness makes him act like a dog.

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[[folder: Newspaper Comics ]]

* In ''BeetleBailey'', Beetle once hypnotises Sarge to think he's whatever he secretly wants to be, making him act like a lion. He also accidentally affects General Halftrack, but he doesn't "become" an animal: "Have you gone mad! I'm an airplane!" (Paraphrased.)
* In ''ComicStrip/CalvinAndHobbes'', Calvin can transmogrify himself into any kind of animal, but from his mom's perspective he's always shown as a six-year-old boy.

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[[folder: Webcomics ]]

* In [[http://www.giantitp.com/comics/oots0767.html this]] ''[[Webcomic/TheOrderOfTheStick Order of the Stick]]'' comic, Haley uses a potion that [[RPGMechanicsVerse increases her ability to bluff]] to the point that she can make anyone believe practically anything. Amongst other BlatantLies, she deals with one guard by convincing him that he's a wallaby, causing him to irately hop off to find a wizard to undo the spell.
* Inverted in ''SkinHorse'' with Phil the Mynah, an UpliftedAnimal who thinks he's human.

[[/folder]]

[[folder: Western Animation ]]

* In the WesternAnimation/LooneyTunes cartoon "Hare Brush", Elmer Fudd thinks he's a rabbit. He gets put in a mental institution, where he escapes, leaving BugsBunny in his place. Bugs gets convinced by the psychiatrists that he's "Elmer J. Fudd, millionaire. I own a mansion and a yacht." He then goes rabbit hunting, and Elmer is the rabbit he's hunting. Ultimately subverted, though, as Elmer!Bugs gets arrested for tax evasion. Elmer knows he's not a rabbit; he's faking it so he doesn't go to jail.
-->'''Elmer:''' I may be a scwewy wabbit, but I'm not going to [[TheAlcatraz Owcatwaz]]!
** In another of the ''WesternAnimation/LooneyTunes'' shorts starring PorkyPig and Charlie Dog, Porky is DrivenToMadness and at the end starts acting like a dog.
* In the SeriesFinale of ''WesternAnimation/PoundPuppies1980s'', the stress of running the pound (and inability to escape it, even when on an attempted vacation) eventually broke the evil aunt Katrina Stoneheart, causing her to conclude that maybe she was a dog, too.
** An episode of the [[WesternAnimation/PoundPuppies2010 reboot]] had dog catcher [=McLeish=] hypnotized into believing he was a dog, while retaining his human memories.
* ''WesternAnimation/JackieChanAdventures'': One episode had EvilBrit Valmont spray Uncle with a gas that causes amnesia. Valmont says, "Fare thy well, you old goat!" Uncle, who was wondering who he was, said, "Oh! I am a goat!" So he starts walking and running around on all fours, nibbling on stuff and bleating!
* Rat King from ''WesternAnimation/{{Teenage Mutant Ninja Turtles|1987}}'' thought he was actually a rat.
* A gag in the ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' episode "Read It and Weep" involves barking dog noises during a chase, which turn out to be coming from a mental patient pony ([[FanNickname known to fans]] as "Barking Mad" or "Screwloose") who escaped from the hospital.
** Big Macintosh ends up in on this when [[RealityWarper Discord]] has his way with the town of Ponyville in "Return of Harmony, Part 2".
* In ''WesternAnimation/TheSimpsons'' softball episode, one of Mr. Burns' team of ringers is hypnotized into thinking he's a chicken. He continues to think he's a chicken for the rest of the episode.
* Papa Smurf and Gargamel were both given magical delusions of doghood in an episode of ''WesternAnimation/TheSmurfs''.
* Happened on one episode of ''Series/MonstersVsAliens'', thanks to some AppliedPhlebotinum. Sqweep wants a puppy, so B.O.B. volunteers to act as a dog for him, but can't get the behavior right. To remedy this, Sqweep makes a device to alter B.O.B.'s brain waves; but as B.O.B. has no brain to speak of, the ray just goes through him and ricochets all over the base, making ''everyone else'' think they're dogs.
* The Creator/TexAvery-directed Creator/WalterLantz short "Crazy Mixed-up Pup" is about a man and his dog who are run over and treated by paramedics, who accidentally got human and canine plasma switched. When the man returns home, he starts exhibiting dog behavior, while the dog stands on his hind legs and talks. [[spoiler:In the end, [[HereWeGoAgain the same thing happens to his wife and her cat]].]]

[[/folder]]

[[folder: Real Life ]]

* Actually a real mental illness, called clinical lycanthropy.
* According to a persistant rumor, [[UsefulNotes/TheAmericanCivilWar Confederate]] Gen. Richard S. Ewell had occasional delusions that he was a bird.
* There is a (false, fortunately) urban legend about a man who, after taking a massive amount of LSD, became convinced he was an orange. ''Permanently.''
* Many cultural/religious/etc. beliefs thought that simply ''wearing'' the pelt (though sometimes bones as well) of an animal would cause you to take on the traits of that animal. In fact, the term "Berserk" comes from an ancient belief that wearing a bear pelt would cause you to transform into a bear.
* "Pet Play", a subset of UsefulNotes/{{BDSM}}, where the submissive acts and is treated like an animal (usually a cat, dog or horse).
* Feral children who have been [[RaisedByWolves raised by dogs]] will exhibit canine behaviour, even after they have been properly civilized.

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