The creatures have short, near spherical bodies, with an eight-part mandible which opens up to reveal a circular mouth. Eyes and other sensory organs are located below the mandible, and there are structures on the back which open and close, possibly serving as a breathing apparatus. The body ends in an extremely long, hollow tail which shoots darts made from the uranium that the aliens metabolize. Their bodies are sustained by four insectile legs, each ending in a powerful claw. They can use the claws to rapidly dig themselves into the soil.
The exoskeleton appears of mineral origin and even has a metallic texture on some parts. They are hard to kill with bullets, but very vulnerable to explosives. It is hinted that their body fluids might be highly combustible.
Despite traveling in huge numbers within their ship, the aliens rarely attack in groups. Unquestionably intelligent creatures; they communicate with a verbal language of some kind, and only attack targets which pose a direct threat to them (ex: men, but not horses).
The aliens' vessel is of spherical shape and opens up in the same fashion as the creature's maw.
- High Plains Invaders (2009)