Invasion of the Body Snatchers is a 1978 horror film starring Donald Sutherland, Veronica Cartwright, Brooke Adams, Jeff Goldblum, and Leonard Nimoy.
Plant-spore, blown on the "solar wind," lands on Earth and attaches to plants. Those then infect people, duplicating them while they sleep. The story follows Elizabeth (Adams) and Matthew (Sutherland), two health department employees, as they come into contact with the aliens. Elizabeth, first, realizes that her husband (Art Hindle) has been duplicated, but of course no one believes her because it's ludicrous. Matthew takes her to see his famous shrink friend (Nimoy) and they run across their hippie mud-bath owning buddies (Goldblum and Cartwright), and they all figure it out. But by the time they start calling people and calling attention to the problem, it's too late; the aliens have duplicated enough people that there's nothing they can do but run. The movie ends with Cartwright's character approaching Sutherlands, and that famous scene of him pointing and giving the alarm scream.
Invasion jumps right in; Hindle's character is duplicated right away and most of the meat of the movie makes it clear (to the audience) what's happening. The conflict comes down to making other characters understand what's happening, and then the creeping horror as more and more people become "snatched." Also creepy is how benign the duplicates are; they aren't hateful or violent, and they don't want to eat people. They just want to survive, and this is how they do it.
The background business is also amazing; garbage bins are full up with gray gunk - which is the remains of people. Plants are everywhere in shots, and if you watch you can see people glance at each other, knowingly, getting less subtle as the movie goes on.
Invasion is a good exercise in paranoia and the fear of one's neighbors; the novel it's based on has a happier ending, in which the aliens leave. I kind of like the creepy, almost silent (except for that god-awful scream) ending in this film. I haven't seen the other adaptations, though.
My Grade: A-
Rewatch value: Low
Next up: The Iron Giant