The title character in the 1979 film Alien kept surprising us -at least the first time we saw the movie. It changed into several forms over its life cycle, from an egg to a face hugger to a chest burster to a xenomorph. It was quite otherworldly, but still resembles creatures of earth, some that lived millions of years ago and others that still exist. Each phase of the alien's life was inspired by a different species.
The design of the "chestburster" and the full-grown xenomorph ("alien-shaped thing") is based on Giger's "Necronom IV", an artwork created in 1976. The surrealist drawing shows a female figure composed of different parts of insects, parts of vertebrates and even fossils. Giger used the fossils of 300 million-year-old crinoids, commonly called sea lilies, on display in the Aathal dinosaur museum as a source of inspiration. The earliest known crinoids date back to the Ordovician (some 450 million years ago).
It wasn't just the look of the alien that came from nature, but its behavior and life cycle, too. The team that produced Alien apparently found the scariest things about different animals and combined them to create the horror of Alien. Geologist David Bressan looks at the various real-life inspirations for the different phases of the xenomorph, at Forbes. -via Real Clear Science