An alien takes over human bodies, then switches to other humans

The Earth is invaded by alien parasites—AKA 'slugs'—that ride on people's backs and control their minds.

A small-town doctor learns that the population of his community is being replaced by emotionless alien duplicates.

The residents of San Francisco are becoming drone-like shadows of their former selves, and as the phenomenon spreads, two Department of Health workers uncover the horrifying truth.

In the winter of 1982, a twelve-man research team at a remote Antarctic research station discovers an alien buried in the snow for over 100,000 years. Soon unfrozen, the form-changing creature wreaks havoc, creates terror... and becomes one of them.

The mind of Pierre Bérard, a successful middle-aged architect, is torn between his unstable present with Hélène, his younger lover, and his happy memories of the past with Catherine, his ex-wife; but his true destiny awaits him at a crossroads on his way to Rennes…

When Environmental Protection Agency inspector Steve Malone travels to a remote military base in order to check for toxic materials, he brings his family along for the ride. After arriving at the base, his teenage daughter Marti befriends Jean Platt, daughter of the base's commander, General Platt. When people at the base begin acting strangely, Marti becomes convinced that they are slowly being replaced by plant-like aliens.

Aliens who take on the form of humans are invading Earth, with the ability to manipulate women on a psychological level.

An alien is dispatched from a faraway galaxy to take over the Earth by "duplicating" humans and creating a race of zombies.

Alien ship crash-lands on Earth and the creature inside starts taking over people's bodies.

In San Francisco, a group of clones devoid of emotion are slowly being replaced one by one by humans.