The design of the Alien in the 1979 film "Alien" is credited to Swiss surrealist and artist H. R. Giger. The design originated in a lithograph titled Necronom IV and was refined for the series' first film. The practical effects for the Alien's head were designed and constructed by Italian special effects designer Carlo Rambaldi. Overall the species' design and life cycle have consistently and extensively been augmented throughout each film. With the color of this extraterrestrial species, some minor inconsistent variations are seen.

This 1979 film is a science fiction horror film directed by Ridley Scott and written by Dan O'Bannon. It is based on a story by O'Bannon and Ronald Shusett. It follows the crew of the commercial space tug Nostromo who encounter the eponymous Alien, a deadly and aggressive extraterrestrial set loose on the ship.The film stars Tom Skerritt, Sigourney Weaver, Veronica Cartwright, Harry Dean Stanton, John Hurt, Ian Holm, and Yaphet Kotto. This film launched the acting careers of several stars; they got leading roles.

The monster, an Alien (a "murderous thief"), made its film debut in the movie "Alien". It reappeared in the sequels "Aliens" (1986), "Alien 3" (1992), and "Alien Resurrection" (1997), as well as the crossover films "Alien vs. Predator" (2004) and "Aliens vs. Predator: Requiem" (2007).

More Info: en.wikipedia.org