''The Hidden'' is a 1987 sci-fi action/horror buddy cop film directed by Jack Sholder, starring Michael Nouri and Creator/KyleMacLachlan.
In Los Angeles, a spree killer is finally stopped by the L.A.P.D., only for the dead killer's crime spree to be continued by seemingly unrelated people with no priors. When an FBI agent shows up with surprisingly detailed knowledge about the culprits, it soon becomes clear that the killer can not only switch bodies, it isn't even from Earth...
!!This film provides examples of:
* AlienAmongUs: Lloyd Gallagher, the FBI agent, is actually an alien inhabiting someone's body. He is quite well adapted to life on Earth, but is still awkward and doesn't know how to take a aspirin, for example.
* BadIsGoodAndGoodIsBad: When the evil parasite inspects a warehouse storing guns and stolen antiques belonging to some criminal he just murdered, he turns on a record player which proceeds to play a folksy jingle. After listening to it for a few seconds he angrily destroys the record; his evil taste in music apparently doesn't extend beyond death metal.
* BankRobbery: The film opens with the evil parasite robbing a bank, as seen from a black and white security camera. The cops later say that he had robbed another seven banks during his crime spree in that body.
* BittersweetEnding: [[spoiler:The evil alien is finally destroyed by Gallagher, but officer Thomas Beck is killed in the process. The good alien transfers his essence to his parter's dying body to ensure that his family won't be left alone.]]
* BodySurf: A PuppeteerParasite-like alien takes over various people in Los Angeles and uses them to commit thrill crimes. He is chased by a member of a different PuppeteerParasite species who is inhabiting the body of an FBI agent.
* BuddyCopShow: The movie features one such couple, with officer Tom Beck being the emotional and down-to-earth one and FBI agent Lloyd Gallagher (really a PuppeteerParasite inhabiting a human body) being the stoic, [[TheSpock logic-minded]] but [[AlienAmongUs awkward]] one. Interestingly, because Gallagher has a [[ItsPersonal very personal]] reason to go after the bad guy, he's both TheStoic and the CowboyCop of the duo.
* CantHoldHisLiquor: Detective Tom Beck offers his temporary FBI partner Lloyd Gallagher a beer after he invites him for dinner with his wife. Gallagher, who unknown to his partner is actually an alien cop [[PuppeteerParasite residing in a human host]], apparently can't stand the taste and has a hangover from just a few sips.
* CassandraTruth: The good alien is more than aware of this and prefers to keep his human partner out of the loop concerning the body-jumping alien parasite they're both pursuing. When he does finally tell him the truth about space aliens after his cover identity is exposed as a fake, he is thrown in a jail cell because his partner thinks he's pulling his leg.
* ChekhovsGun: Early on, one policeman shows the two main characters a flamethrower he grabbed from some kids who just happened to carry one in the street. Because it has nothing to do with the scene and disappears just after, it's pretty obvious it will be used against the body-snatcher alien.
* DarkActionGirl: The stripper, due to the alien pulling a BodySurf on her.
* DecoyProtagonist: [[spoiler:Tom Beck, who is fatally wounded by the alien-possessed Willis close to the climax, leaving Gallagher to the save the day an complete his mission to destroy the alien BigBad. Beck later dies in the hospital in the aftermath and Gallagher himself later transferred into his body to make sure Beck's family would not be alone without him in their lives.]]
* DirtyCop: [[spoiler:[[DaChief Lt. John Masterson]] and [[CowboyCop Det. Cliff Willis]] unwillingly border on this due to the alien villain possessing them to get close to its targets.]]
* DistractedByTheSexy: When the alien is pulled over by the cops while [[GrandTheftMe wearing a stripper's body]], it uses its "assets" to make them drop their guard before opening fire on them.
* TheDogIsAnAlien: 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.
* EvilIsPetty: The alien criminal is basically, if not an AxCrazy SerialKiller, a small-time crook who loves to commit robberies ForTheEvulz. However, when it targets Senator Holt, it upgrades its agenda and decides to turn from a petty thief to a terrorist to embark on becoming PresidentEvil.
* EvilOldFolks: The alien inhabiting Jonathan Miller fulfills this.
* GrandTheftMe: An alien slug takes over the bodies of humans as unsuspecting prey and treats it like a joyride. It just wants to listen to death metal, drive expensive cars, rob banks, and blow things up. For fun.
* ImpersonatingAnOfficer: The good alien parasite poses as an FBI officer so it can enlist the help of local human law enforcement to hunt down the evil alien parasite who killed his partner. Admittedly it's a SpaceCop in its own right, but pretty far outside of its normal jurisdiction.
* ItsPersonal: [[SpaceCop Lloyd Gallagher]] has been hunting the evil alien parasite ever since it killed his partner on the planet Altair, so [[CowboyCop he's a lot more reckless]] than the human officer he's paired up with.
* ListOfTransgressions: When the alien PuppeteerParasite villain's first onscreen body is near death in the hospital, a doctor takes offense to the police officers' relief, saying that no one deserves to die like that. One of the officers responds thus:
-->He killed twelve people, wounded twenty three more, stole six cars, most of them Ferraris. Robbed eight banks, six supermarkets, four jewelery stores and a candy shop. Six of the ones he killed he carved up with a butcher knife. Two of them were kids. He did all that in two weeks. If anyone deserves to go that way, it sure in the hell was him!
* ManIFeelLikeAWoman: The villain is a parasitic alien who jumps around between various human bodies. All are male, except for one, a stripper played by Claudia Christian. As soon as the alien makes the switch, he reaches down and ... you know the rest.
* NoNameGiven: Neither the evil or good alien parasites in the story reveal their true names. The good one only adopts a human cover identity to make it easier to conduct its work.
* TheOnlyOne: Spoofed when the Chief says that when the cop protagonist is reassigned:
-->"My department will then crumble, crime will run rampart, the city will fall into ruin, rampaging hordes will control the streets and life as we know it will end!"
* OrificeInvasion: The alien parasite burrows into and out of mouths several times during the movie. One scene used a prosthetic head to show the process in gory detail; upon seeing that scene on film, the actor whose likeness was on the head was physically ill.
* OutWithABang: While possessing the body of a stripper, the PuppeteerParasite-like alien screws a man to death in the parking lot. It's a bit unclear exactly how this is done, as there were no obvious wounds on the victim, nor does the alien seem able to literally consume a person's lifeforce.
* PresidentEvil: Alluded to but never realized. Towards the end, the evil alien who has been going on a mass-murdering rampage throughout Los Angeles throughout the entire film, takes over the body of a U.S. Senator. He announces that he wants to become President.
* PuppeteerParasite: The antagonist is an icky alien resembling a mosquito larva, which forces its way down people's throats and does the BodySurf routine. One of the two main characters is also one, but from another alien species that doesn't need to change body nearly that often.
* RapeDiscretionShot: Subverted. The parasite uses his current body to assault a stripper after gaining an apparent interest in sexy women before the shot cuts away. It would hardly be out of character for a thrill-seeking spree killer to turn to sexual violence, but it turns out he was more interested in [[GrandTheftMe taking over her body]]. It does, however, literally screw another guy to death in the stripper's body.
* RayGun: The good alien has a special type of gun that is required to kill the evil alien, but he needs it to leave its human host first as it incinerates their own kind but is harmless to human tissue.
* SheetOfGlass: Taken UpToEleven in the DramaticChaseOpening. Two men are carrying a sheet of glass across a park for no apparent reason when the BodySurf alien comes roaring up in a stolen car. He not only drives through the glass, he also [[KickTheDog runs over the two men in the process]].
* ShowingOffTheNewBody: The body possessing space alien villain starts out only possessing the bodies of men. The first time it possesses the body of a female stripper, it spends some time exploring the differences.
* SpaceCop: The good body-snatching alien (who poses as an FBI agent for most of the film) eventually reveals himself to be an extra-terrestrial police officer who has been pursuing the rampaging evil bodysnatcher across several planets after it [[ItsPersonal killed his partner]].
* SuperToughness: Any human host that the evil parasite possesses becomes durable enough that they need to be shot over fifteen times before it decides to swap it for a better meatsuit. The cops note that one vacated host simply bled to death, because the alien wasn't around anymore to keep it alive.
* TerroristsWithoutACause: The alien criminal seeks to become this by taking over a senator's body to make a breakthrough in pulling off the biggest intergalactic crime of its life.
* VillainSong: While the alien BigBad does not have one, the in-universe heavy metal music it listens to reflects on its destructive, yet daredevil lifestyle and one from a car radio which its lyrics reflects on the alien getting use to inhabiting a female body.
* VillainWithGoodPublicity: Soon after taking over the senator's body, the alien is greeted with applause after simply saying that it wants to be president.