Some sort of alien lifeform comes to Earth, and, to avoid attention from TheMenInBlack, disguises itself as a domestic animal, usually a dog. Sometimes the alien happens to already look like a dog, while others may transform themselves using VoluntaryShapeshifting or AppliedPhlebotinum.

The latter variant raises some questions as to why the alien wouldn't choose to disguise itself as a human, giving itself far more freedom within human society. However, given that their disguise may not be perfect, or that they may be unfamiliar with human social norms, this may be a sensible decision. A dog that acts or looks a little bit odd is less likely to attract attention than a human who acts strangely or [[UncannyValley looks creepy]].

The alien often finds itself adopted as a pet, usually at least somewhat willingly. After all, a family who is willing to provide food and shelter seems like a reasonable alternative to living on the streets avoiding TheMenInBlack and dog catchers, and the alien probably reasons that it is capable of escaping if it needs to.

This trope comes in both benign and malevolent variants. The former tends to result in ABoyAndHisX.

The most common variant of this trope involves a dog that's an alien, however, it can also apply to other types of animals, and "alien" can be substituted for virtually any sentient fictional species. If the alien is not intentionally disguising itself as a dog, but gets mistaken for one anyway, it's ThatsNoDog.

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!!Examples

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[[folder: Advertising ]]

* A Budweiser commercial opens with a dog coming out of a house. It runs to the middle of nowhere and gets taken on board an alien ship. The ship takes the dog to the alien leader's quarters on another planet, where the dog presses a button on its collar and reveals that it is actually an alien in disguise.
** What did he learn on Earth? "WAZZAAAAAP!"

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[[folder: Comics ]]

* The comic book story "[[http://www.misterkitty.org/extras/stupidcovers/stupidcomics149.html Rover's a Good Dog!]]" from ''Forbidden Worlds'' #106, which is about a race of evil alien dogs sending an agent out in the guise of a domesticated Earth dog to photograph the plans of a top-secret American weapon. However, the agent becomes compassionate to the inventor and his family, and ultimately doesn't have the heart to go through his mission, instead sacrificing himself to save the family.
* In ''TheIncredibleHercules'', we find out that [[spoiler:Kirby, the coyote pup that Amadeus Cho had adopted, had been long-replaced by a [[{{Shapeshifter}} Skrull]] imposter. While the real coyote was safe and unharmed, the Skrull!coyote had accompanied Cho for the better part of a year before TheReveal.]]
* KryptoTheSuperdog
* ''Comicbook/{{Runaways}}: "My dog's a [mystically cloaked] genetically engineered psychic dinosaur from the 87th century."''

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[[folder: Film ]]

* The Creator/DisneyChannel Original Movie ''Can Of Worms'', has the protagonist new sidekick be an alien talking dog.
* Stitch from ''Disney/LiloAndStitch'' pretends to be a dog despite looking more like a blue koala. According to the tie-in comics, however, it explains that one donor of his genetic composition was from an Earth puppy, so he was intentionally created to resemble one regardlessly.
* Frank the Pug from ''Film/MenInBlack''. The AnimatedSeries revealed that under his dog suit he looks like a green dog. Also he is apparently prone to dog like behavior and it's not part of the disguise.
* In ''Film/IAmNumberFour'', [[spoiler:John/Number Four's dog Bernie Kosar shapeshifts into a more monstrous, distinctly more extraterrestrial creature (that still resembles a dog) known as a Chimera to pull a BigDamnHeroes, engaging another alien monster in combat and eventually killing it.]]
* Subverted in ''Film/TheCatFromOuterSpace'', in which the alien looks exactly like a cat in his natural state and doesn't do much to pretend to be one except refrain from speaking. If the humans assume he's a cat, it's not his fault.
* In "Phantoms" a gelatinous being can send out autonomous drones to do tasks. One of these is a white dog that fools soldiers and gets close enough to send out tentacles and kill them. Later, the dog is used to keep tabs on the surviving humans.
* In "The Hidden" a parasitic alien creature hides in other beings and uses them. It temporarily uses a dog, but (as in the original "Who Goes There?") it wants to be a man, not a dog.
* UpToEleven in ''Film/GoodBoy'', where it turns out ''every'' dog on Earth is actually an alien from another planet, though many have gone native and forgotten they were originally sent to conquer Earth.

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[[folder: Literature ]]

* In the short story, "Puppet Show", by FredricBrown, an old prospector brings a very ugly Rubber Forehead Alien out of the wilderness on muleback, and the captive is questioned by the military. After a bit of subterfuge, it turns out that the captive is a robot, and the prospector declares himself to be the real alien. The interrogator expresses relief that the master race of the galaxy looks human after all... at which point, the prospector reveals itself to be a robot as well, and the ''mule'' asks what a "master race" is and why its appearance should matter.
* Trillian's mice from ''Literature/TheHitchhikersGuideToTheGalaxy1'' turn out to be aliens in disguise. So are all other mice, wild ones included, but Trillian's are specifically implied to be albino laboratory rodents, hence domesticated.
* The alien in ''Film/TheThing1982'' masquerades as a dog for a while.
* In JohnScalzi's ''Agent to the Stars'', the gelatinous Blob-like alien the protagonist meets eventually takes on the form of a dog in order to come off as more appealing to humans.
* Literal in ''Literature/{{Animorphs}}'', where the Chee bonded the essence of their Pemalite masters to wolves to create dogs.
* In ''Turning Point'', the first book of Lisanne Norman's ''SholanAlliance'', the CatFolk Kusac hides his sapience by pretending to be one of the local felines. Carrie then takes him into her home on account of his injuries.

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[[folder: Live Action TV ]]

* Series/{{ALF}} did this from time to time, with varying degrees of success. For instance, on one occaision, he was seen by a hobo who thought he was a kangaroo... and promptly leapt off the train they were riding.
* In ''Series/{{Supernatural}}'' there are {{Skinwalker}}s who can take the form of a dog. One of them becomes attached to the family he lives with.
* This happened once in an episode of Star Trek: The Next Generation

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[[folder: Video Games ]]

* In ''LegacyOfTheWizard'', Pochi looks like a dog when hanging around the family home, but when selected as a playable character he turns into something that is definitely not a dog.

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[[folder: Web Comics ]]

* Ambis in ''Webcomic/{{Jix}}'' are frequently mistaken for dogs, despite the titular character having [[AmazingTechnicolorPopulation blue]] fur among other things. Eventually it is determined that they share a common ancestor with [[AlienAnimal foxes]].

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[[folder: Western Animation ]]

* ''WesternAnimation/ConanTheAdventurer'': While not an alien, Needle, a baby phoenix, would occasionally pretend to be a parrot to avoid drawing attention.
* The cat in ''KidVsKat'' is an alien that looks like one of those hairless cats.
* ''InvaderZim'': GIR disguises himself as Zim's pet dog. ... his disguise being a lame costume with a zipper and a tongue sticking out.
* {{Futurama}}'s Nibbler is a bit of an odd example as everyone knows he's an alien. What they don't know is that he's a member of an incredibly advanced alien race. And he can talk.
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