Alien

In his 1979 classic, Alien, Ridley Scott created one of the most memorable extraterrestrial antagonists ever to hit the screen. Designed by renowned artist H. R. Giger, the hissing, slime-dripping, acid-bleeding alien is immediately recognizable and utterly terrifying. As the film forebodingly begins, Ripley (Sigourney Weaver) and Dallas (Tom Skerritt) lead a crew of interstellar miners aboard the Earth-bound ship Nostromo to investigate a downed spacecraft after receiving what seems to be a S.O.S. transmission. What awaits them, of course, is not a group of stranded travelers. In scene after seminal sci-fi scene, the crew begins to realize what they're dealing with—an emotionless, perfect fighting machine, able to pick people off seemingly at will. A surprisingly impressive cast (including British heavyweights Sirs John Hurt and Ian Holm) lends an air of believability to the moments between attacks, and Scott's masterful direction, coupled with the deliberate pacing of the story, creates palpable tension. Though there's little action for the first 30 minutes or so, an underlying unease permeates the lonely Nostromo, and the claustrophobic atmosphere is heightened once the deadly stowaway is revealed. Though he clashed creatively with Scott, composer Jerry Goldsmith delivered an eerily minimalist score that underlines the dire mood brilliantly, adding yet another layer to an already complex and expertly crafted thriller.