Alien (1979) changed the face of horror and sci-fi. (You got your sci-fi in my horror; you got horror in my sci-fi . . . it tastes great!) Lured by the H.R. Giger-created creature, all two snapping and drooling jaws of it, audiences flooded theaters to be frightened like never before. From the hungry baby beast implanted in John Hurt's belly eating its way out, to the discovery that the alien bleeds acid, which burns through the spacecraft's outer hull, the movie offered a new kind of monster not seen since the advent of zombie pictures. It may be true that in space nobody can hear you scream, but sadly no one can see you nude either. Besides Sigourney Weaver, who fights the ghoul in her tiny underwear, the movie is all blood and guts and no boobs and butts. Still, this is one illegal alien no one would want mowing their lawn.