Originally, the Alien creature was intended to be an advanced, cultured civilization with an incredibly complex life cycle, involving the use of living hosts for gestation, followed by an incredibly violent and aggressive adolescent stage. With such a complicated means of procreation, the species had developed stringent religious beliefs based around their method of reproduction, involving the impregnation of sacrificial animal hosts inside ornate stone pyramids.
In Dan O'Bannon's original script, it was inside one of these pyramids where Dallas, Kane and Lambert discovered the Xenomorph Eggs, rather than on the derelict ship — the idea being that the derelict and its crew had simply stumbled upon the structure and succumbed to the creatures it contained previously, foreshadowing what would happen to the Nostromo. The pyramid was going to be filled with elaborate hieroglyphics, similar to the pyramids found on Earth, and featured a prominent central sacrificial chamber where hosts were inseminated atop a stone plinth (an idea notably recycled/adapted in Alien vs. Predator).
When Walter Hill and David Giler performed rewrites on Alien's script, the structure's design and background was altered, becoming a cylindrical silo of human origin with an industrial, utilitarian interior; the Eggs within were intended to be a human bioweapon created by scientists, with the Nostromo crew lured there so they could be unwitting test subjects. A final iteration of the structure designed by H. R. Giger reinstated its extraterrestrial origins, with its appearance matching the bio-mechanical aesthetic he had applied to much of the rest of the film.
The entire Egg Silo concept was cut before filming due to budget constraints. According to director Ridley Scott:
- "The pyramid and the derelict — two different elements — were still the subject of a seesaw debate when I came on the project. I would love to have shot it, but the more I thought about it the more I realized it would have been wonderful in a three-hour version. What finally cracked it was the budget. We just had to get rid of it. And you know, sometimes financial practicalities force you to do a certain amount of editorial work, and I'm glad we simplified it."
- ―Ridley Scott, regarding the removal of the Egg Silo
- The Xenomorph Hives seen on Earth in Aliens: Nightmare Asylum greatly resemble Giger's concept artwork of the Egg Silo.
- "Weyland-Yutani Archives - Alien Unseen Part One: Ridleygrams". Retrieved on 2013-04-29.
- "Monster Legacy - StarBeast — Prologue: Alien, Dan O'Bannon's Cosmic Horror". Retrieved on 2015-08-07.
- "Strange Shapes - The Derelict/Pyramid/Silo". Retrieved on 2014-10-24.
- "Weyland-Yutani Archives - Alien Unseen: The Human Derelict and Pyramid". Retrieved on 2013-11-07.