A chap with a beard disappears in a flash of light then he wakes up naked in a forest two years later. He changes a bit in the time he's gone, and instead of throwing himself a welcome home party with a big cake, he starts killing people and inserting alien eggs into their bodies via a long, fleshy egg-pipe that comes out of his mouth. It all gets very bloody and then ends.
It's absolutely straight-up, with nothing complex or contrived, just a decent, well made horror film with some excellent, splatty practical effects. The only flaw is some of the acting is a little weak, one character in particular is amusingly bad in some scenes, otherwise it's a real little cracker and worth seeking out.