In rural Pennsylvania, one of life's great losers looks up from behind his gas station counter and notices that a big old Buick is still sitting out front with its driver nowhere in sight. After a quick search, he can't find the driver but fears he may have fallen into the river, so he calls the state police. When the police arrive, they cannot find any trace of the man and take the car away as potential evidence. Only... only it's not really a car. There's no way it can drive, it's missing essential parts and looks like it never had them and seems more like it teleported in judging by the lack of mud.
And that's just the start because ''things'' come out of it - the story--as written by Creator/StephenKing--is framed as the current Sergeant Commanding and some other officers explaining the thing to the traumatized son of an officer who was tragically killed by [[ContrivedCoincidence that same loser]] years later.
* AlienGeometries: It seems to have a direct connection to another universe, perhaps another world linked to Franchise/TheDarkTower.
* AlienSky: [[spoiler: In the climax, Sandy pulls Ned out of the car, and in the process, gets a brief glimpse of the world on the other side, an alien world with a deep purple sky, along with remnants of the people absorbed by the Buick.]]
* AmbiguousSituation: Basically the point. You don't get many answers by the end. There are multiple theories, but you don't know if any are true.
** Curiosity killed the cat, but satisfaction brought him back.
** Come closer, children. See the living crocodile.
* AskAStupidQuestion: The following conversation between Tony Schoondist and George, when the former orders the latter to get a pair of gerbils plus a cage so they can test if being inside the Buick is dangerous:
-->'''George''': Should I get them some food, too?
-->'''Tony''': Absolutely not. We're going to buy a couple of gerbils and then let them starve to death out in the shed.
-->'''George''': [[SarcasmBlind Really?]] That seems sort of mean to-
-->'''Tony''': Get them food George, yes.
* AssholeVictim: [[spoiler:The Neo-Nazi Brian Lippy]], who was arrested for reckless driving and beating his girlfriend, is "eaten" by the Buick after it's implied he tried to hide in the trunk.
* AttackOfTheKillerWhatever: Well, it ''looks'' like a car, anyway.
* BaitAndSwitch: In the final chapter, set 4 years after the rest of the story, it is strongly suggested that [[spoiler:Ned is killed in a car crash; the car was Curtis' chevrolet and it is mentioned that SC Dearborn will have to inform the victims mother and sisters]]. The twist: [[spoiler: it was actually Eddie J. who was in the car, having bought it from Ned earlier. Ned is alive and well and has just joined Troop D]].
* BittersweetEnding: [[spoiler:The Buick remains a complete mystery by the end of the novel... but newly hired deputy Ned notices that the once-pristine car is showing signs of damage, meaning it's dying and whatever threat it represents will soon fade.]]
* BizarreAlienBiology: The creatures that come out of the Buick. In addition to the visually apparent weirdness, there is something about their chemical makeup that makes them start decaying almost instantly in our atmosphere. An attempted AlienAutopsy does not go well. [[spoiler: Sandy later realizes that if some of the blood-like black substance that squirted out of the bat-creature had gotten into Curtis' mouth, he would have died.]]
* CallASmeerpARabbit: Various things come out of the trunk of the Buick. They tend to get called things like "birds", "fish", and "leaves" when it is very clear that that is not what they are at all; Ned's repeated failure to grasp this point irritates Sandy immensely.
* ContrivedCoincidence: Subverted. Curtis is eventually killed in a hit and run by the same guy who called the police about the Buick, but Sandy speculates that the Buick somehow arranged it.
* CoolCar: It'd be an impressive vehicle if it actually, you know, was a vehicle.
* DeliverUsFromEvil: Discussed in its gender-flipped form. One character mentions that sometimes crooks straighten themselves out after becoming fathers, but that more often it just means that they have one more person to victimise.
* DepartureMeansDeath: Things from the trunk can't survive in our world, and it's assumed stuff from ours wouldn't survive there either. No one knows why, although it's theorized it's due to the change in the air.
* DrivenToSuicide: [[spoiler:Eddie at the end, though it was set up to seem as though it was Ned.]]
* EldritchAbomination: One officer notes that looking at the things that come out of the trunk made him feel like ''[[MindRape his EYES were being raped]]''.
* EvilDetectingDog: Mister Dillon, Troop D's German Shepherd mascot, reacts violently to the car whenever he gets near it. It's enough proof to the cops that the car is indeed something bad.
* ExtremelyShortTimespan: Zig-zagged. The bulk of the story is set on a single evening with all members of Troop D telling Ned about the history of the Buick and Curtis' time on the force. The stories they tell him however span a time period of 25 years.
* FromBadToWorse: The "worst day ever", as described by Shirley, starts with [[spoiler:a chemical tanker colliding with a school bus, causing all of Troop D to head to the accident, leaving her alone with Huddie and Mister D. Eddie pulls over his old high school bully Brian Lippy, who has since become a neo-Nazi drug addict, for beating his girlfriend. He and his partner George take him back to the troop, where they discover to their horror the Buick has given ''live birth'' to a HumanoidAbomination, which they are forced to kill. Mister D ingests some of the creature's flesh, suffering a horrifying death. Finally, Brian Lippy escapes custody in the confusion, and is "eaten" by the Buick while hiding from the troopers]]. Yeah, it was a pretty shitty day indeed.
* HauntedTechnology: The Buick.
* HumanoidAbomination: The mysterious driver of the Buick that originally left it at the gas station at the start of the story, and who disappeared behind the building. The gas station attendant described his ear (the only feature he saw clearly) as looking "melted, like he'd been in a fire", and he had a very odd posture. Outside the novel, said driver is generally theorized to be a [[Franchise/TheDarkTower Low Man]].
** [[spoiler:The one thing that makes it out of the Buick's trunk alive sees the officers as just as mind-breakingly horrible as they see it.]]
** [[spoiler:When Sandy gets a glimpse of the world beyond the Buick, he sees Ennis Rafferty's hat lying on the ground with a wooden stake driven through it, as if whoever or whatever found Ennis was afraid he would come back to life.]]
* HumansThroughAlienEyes: [[spoiler:The above creature was not afraid as it was torn to bits, only very, very confused at what these horrible things were doing to it.]]
* ItsPronouncedTroPay: Tony Schoondist's last name is pronounced "Shane-dinks", which Sandy makes a point of saying.
* MercyKill: The first time something comes out of the Buick that lives long enough for the officers to interact with it, [[spoiler: the station dog, Mister Dillon]], goes nuts and attacks it, apparently ingesting some of its flesh. [[spoiler:The poor dog]] starts burning from the inside out, and one of the officers decides to shoot him, as there is nothing else they can do to help him.
* MagicRealism: When the novel isn't about the Buick and the crazy shit that happens because of it, it's a perfectly grounded look at the lives of a group of state troopers. Tellingly, [[spoiler:the Buick only ever claims the life of one of the troopers, while others die throughout the years due to car accidents or suicide]].
* MocksteryTale: It has the attributes of a detective story, but in fact, it is all about coming to terms with the fact that some mysteries ''cannot'' be solved.
* MrsRobinson: Invoked. Sandy wonders if Shirley might be telling Ned so much and so easily because he's good looking and wonders if she might be thinking of "playing Mrs. Robinson", but nothing ever comes of it.
* MyGodWhatHaveIDone: After they kill [[spoiler: the previously mentioned "live birth" creature]], Shirley says "We killed a ''thinking being.'' That's murder."
* NothingIsScarier: [[spoiler: The world on the other end of the dimensional portal in the Buick]] is only glimpsed briefly by the narrator, but in that brief moment, he sees the remains of the people the Buick had drawn in. No bodies, just a boot, a swastika necklace that had belonged to Brian Lippy, a policeman's hat belonging to Ennis Rafferty, and a gun. Someone has driven a stake through the hat, and the gun is rusted. What exactly happened to the people is never revealed.
* NoBiochemicalBarriers: Averted, as the creatures that come out of the Buick pretty much die and sometimes rapidly decompose when exposed to the open air. It's theorized it would be the same for someone going into their world.
* OhCrap: The general mood whenever someone at the station realizes the Buick is ''doing something'' out in that shed...
* PoliceBrutality: Commented on in-story. Sergeant Tony Schoondist notes that small town cops are good enough, but they get a bad rap from bigger cities -- "for every three honest, hard-working cops in Los Angeles, there's two Hitler Youth wannabes on motorcycles."
* PoliceCodeForEverything: Played with; Troop D doesn't standardly have a code for dealing with supernatural cars, but they come up with "Code D" to use in case they need to inform each other about the Buick over the radio.
* PosthumousCharacter: Ned's father Curtis, whose death brought Ned to Troop D and whose obsession with the Buick provides a lot of the story. Other deceased officers make appearances in the flashbacks as well.
* RuleOfScary: This is one of the themes of the book. The creatures that come out of the Buick, and the Buick itself, make no sense by human standards and will probably never really be understood. The same goes for the motivations of the driver who abandoned the Buick; there is no elaboration of who, or more likely, what he was -- just that he drove the "car" to the gas station, left it there, and then disappeared.
* SurrealHorror: Big time.
* TheseAreThingsManWasNotMeantToKnow: The attitude of most of Troop D towards the Buick. Even the ones who do want to know more about it, Curtis and the previous sergeant, Tony Schoondist, don't want to call in any scientists to look at it beyond their usual forensics guy, mainly because they feel it's "theirs" now and don't want to give it away.
** Tony Schoondist tells his officers that the Buick needs to be kept a secret, and points out that it's fallen right into the hands of people equipped to do that.
* UnusuallyUninterestingSight: A running theme throughout the novel is how the Buick is overshadowed by the often mundane, occasionally dangerous, and once in a while lethal life of a state police officer. The Buick may be an otherworldly, inexplicable ''thing'' from somewhere else, but the troopers have other things to do, and have gotten used to it.
* VomitingCop: The horrible things that come from the Buick make several cops throw up.
* WhatHappenedToTheMouse: The driver of the Buick is seen from behind by Bradley Roach, the gas station attendant, and they exchange a few words as he exits the car and walks toward the other side of the building. Then the driver rounds the corner and is never seen again.
* YouCannotGraspTheTrueForm: The Buick itself. The things are incredibly alien and horrible, but you can see them properly. The Buick is speculated to be something along the line of the breathing valve for an EldritchAbomination's scuba gear.
** It's also speculated that, for all the scary power the Buick possesses, the vehicle was left behind because it was somehow ''broken''...