Virn

Virn, a.k.a. "the green planet", is a desolate world covered in green sand. It is a dark planet where neither sun nor moons ever rise in the sky, and it never rains. In spite of this, however, the planet still has Earth-like atmosphere and environmental conditions.

As independently discovered by both Del Tarrant and Kerr Avon, the green sand of Virn is actually a form of life; capable of moving on its own, and projecting some form of energy which interferes with electromagnetic fields in several different ways, from preventing rain on the planet, to interfering with technological systems, preventing ships in orbit from leaving.

When it comes in contact with a human body (or, presumably, other forms of life), the living sand sucks out the cellular energy in order to feed. When food supplies are short, it can preserve dead bodies in such a way that they remain intact and even warm for months or years, enabling the sand to continue to feed upon them. Additionally, the sand is intelligent enough to identify the fittest humans and keep at least one male and one female alive as a potential breeding stock. Liquid water corrodes and destroys the sand.