Rockgnawer

A larva grown inside the nickel-iron of an asteroid: it eats the metal, and the tetrataenite it cannot digest it grows into teeth. It sits in the lode until disturbed; crack the rock with a pick or a mining beam and it bursts from the face and bores into whoever was digging, suit or hull alike. Friction keeps its gut white-hot, and the seams between the rings of its shell glow.