Miles Bennell (Kevin Mc Carthy) is a doctor in the small California town of Santa Mira whose patients start accusing their family and friends of being impostors. They can't explain their suspicions — there are no physical or behavioral changes — but they are still convinced that the people they suspect are no longer themselves. Bennell and his colleague, Dan Kaufman (Larry Gates), initially assume this is merely mass hysteria, a diagnosis which seems to be confirmed when the patients start recanting their accusations.
However, Bennell soon discovers that the patients were right. The people of Santa Mira are being replaced by alien doppelgangers, identical duplicates grown in pods, which replaced them while they slept. Behind their perfect mimicry of humanity, including emotions, is a soulless void. The pod people have no culture of their own, only what they have copied from humanity, and they have no goal beyond survival. Can Bennell, Gates, and Bennell's recently-returned ex-girlfriend Becky (Dana Wynter) warn the authorities and stop the takeover from spreading?
Usually interpreted as a Cold War-era metaphor for Communist infiltration, although some view it more as an indictment of McCarthyism and small-town insularity and conformity. Word of God denies any sort of political message at all, however.
The 1956 film provides examples of:
- Adaptation Title Change: Invasion of The Body Snatchers is based off a novel called The Body Snatchers.
- Bolivian Army Ending: The film ends with Dr. Hill finally believing Bennell and calling the government to warn them. The pod people are still out there, but they're going to get a fight.
- Breaking the Fourth Wall: Bennell shouts at the camera, "You're next!"
- Cassandra Truth: The first few people who notice that someone's acting odd are easily dismissed.
- Cat Scare: Involving a cuckoo clock.
- Divorce in Reno: In 1956, divorce wasn't a topic for polite conversation, whether it be a quickie divorce in Reno or any other kind. Cue the following euphemisms:Becky: I've been in Reno.Miles: Reno?Becky: Reno. Dad tells me you were there, too.Miles: Five months ago.Becky: Oh, I'm sorry.
- Dutch Angle: Used effectively at various points, as in the scene where Miles discovers the pods in the greenhouse.
- The Film of the Book: Adapted from Jack Finney's novel The Body Snatchers, which was first serialized in Collier's magazine in 1954.
- Framing Device:
- The movie was given one by studio executives who wanted a happier ending. In the added prologue, Bennell is dragged into a hospital emergency ward by the authorities, where he recounts the film to the doctor assigned to him. In the epilogue, his story is confirmed by one of the pod truck drivers being rescued from a car crash; the hospital staff immediately call the FBI in an implied happy ending. Director Don Siegel said it almost ruined his intended movie. While a re-edited version of the film more in keeping with Siegel's original vision was supposedly made in 1979, all home video releases have used the theatrical cut with the framing story, as did a special screening held by the Academy of Motion Picture Arts and Sciences in 2005 to honor Siegel.
- Averted in some commercial showings. Since it's contractually allowed to edit for running time, removing the framing device is a common method. These cuts of the film end with the scene described under Breaking the Fourth Wall.
- Hope Spot: The music Miles and Becky hear while hiding in the cave.
- Interrogation Flashback: The film is told this way. The hero is in a hospital psych ward, retelling the events that led to him being found screaming neurotically in the middle of the highway.
- It Was Here, I Swear!: Miles brings his psychiatrist friend to look at his and Becky's pod bodies, but they've naturally vanished.
- Locking MacGyver in the Store Cupboard: They lock Miles and Becky in Miles' own medical office, and he uses his equipment to escape.
- Only Sane Man: By the end, Bennell, and no one left unaffected believes him. Ultimately, however, the psychiatrist realizes Bennell was telling the truth after some medics report having to dig a man out from under a wrecked truck full of giant seed pods.
- OOC Is Serious Business: The Trope Codifier. Prior to this, people acting strangely were usually doing so to further an aim in their story. Here, it's an end unto itself, and pure Paranoia Fuel.
- Pretend We're Dead: Miles and Becky feign emotionlessness to walk through the pod-infested town safely. The other versions followed suit. Thwarted in the 1978 version, where a messed up clone that has a busker's head upon the body of his dog frightens the female protagonist so badly she gives the game away, and in the original she screams on seeing a dog almost run over by a truck.
- Shout-Out to Shakespeare: Becky and Miles paraphrase William Shakespeare twice. "I know a bank whereon the wild thyme blows, Where oxlips and the nodding violet grows" is from A Midsummer Night's Dream. "That way madness lies" is from King Lear.
- Suburban Gothic: Residents of a peaceful suburb in California are gradually replaced by emotionless "pod people" who look identical to them, causing the protagonists friends and loved ones and even some of the protagonists themselves to become villains.
- You Have to Believe Me!: Miles resorts to banging on cars, screaming like a lunatic. One of the pod people lampshades it, saying to let him go because no one will believe him anyway.