As far as aliens go, the Xenomorph is a truly dreadful creature with its humanoid pitch-black exoskeleton, acid for blood, and retractable second mouth. Ironically, it was pure happenstance that Scott ever found his muse for such a horrible deep-space monster. “Funnily enough, I came across a guy called H.R. Giger and if I hadn’t got that monster you would not have had that movie,” he told Yahoo! Movies. It was inside Giger’s book of illustrations “Necronomicon” that Scott discovered a truly disturbing but mesmeric painting titled “Necronom IV.”
As with Moebius, the director was “so taken” by the drawing he flew to Giger’s home in Switzerland and convinced the aerophobic artist to travel by train to England so he could work on the film for ten months. As reported by Vice, Scott had Giger create a “natural history” for the creature to flesh it out into something realistically lethal. Everything about the Xenomorph made it decisively incongruent with any of the sci-fi worlds seen on film at the time.
Of course, hostile aliens have been a staple of sci-fi since the beginning. This wasn’t the cartoonish little green men imagined by your great-grandparents to be living on Mars and even monsters like the rancor of “Return of the Jedi” couldn’t earn a fright like the one in “Alien” could. The Xenomorph ended up being the soul-mate antagonist for Scott’s nightmarish sci-fi vision. And it’s doubtful he would’ve made something so wholly unique had he not pushed from the very beginning to create a film so contrary to “Star Wars.”