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.