Alien

This one starts with a job. A commercial crew is woken early because their ship's computer has picked up something coming from a derelict vessel out in the dark. They go and look, because that is the job, and looking is the worst decision anyone makes all film.

What they bring back on board is not really the point. What the film understands, better than almost anything else in the genre, is that a ship is only safe until it isn't, and that the same corridors you have walked past a hundred times can turn into somewhere you no longer know your way around. It is grubby and lived in, all dripping pipes and flickering strip lights, which somehow makes it worse. Nothing about it looks built for a monster. It just becomes one.

It is slow where it needs to be slow, and then it absolutely is not. If you like your fear to creep up the back of your neck rather than jump out at you, this is the one to put on. Watch it late, watch it with the lights low, and maybe don't watch it if you're eating.

There's a quiet sort of competence in the way this plays out, the kind that only shows itself once everyone around has stopped being useful.