Some exceptionally unsettling elements were thrown together to create the Xenomorph when it first appeared in Ridley Scott's 1979 horror sci-fi, "Alien." Spliced from the nightmares of artist H.R.

It's a big universe out there, and while we're all for exploring it, a specific subgenre of science fiction movies has hinted that it might be a bad idea. Alien invasion movies have come in droves ...