Gammaroid

A gargantuan cousin of the giant snapping turtle, the gammaroid is just as hungry and territorial, and its odd breeding has spawned legends and rituals on many worlds.

In space it poses as an asteroid with smaller rocks clinging to it by gravity. When prey passes, its head shoots out for a 6d4 hull point bite that can swallow small craft, its bony beak ripping through planking. Each claw rakes for 1d6 hull points, or 10d6 against a living foe.

To chase prey, it pulls in head and legs and spins on its axis, flying at starhelm speeds (SR 9, maneuverability F). A ship it rams takes an automatic "ship shaken" critical, with a 30% chance that the serrated shell edge cuts it in half or destroys it. Within an atmosphere, the spin generates a fireball that adds 12d6 damage. It saves this attack mostly for gossamer nobles, its favorite prey.

They breed on worlds bigger than size A, near unstable ground where heat lies within ten miles of the surface. The female burrows to magma, deposits 2-8 eggs there and lets the tunnel cave in behind her. Within 50 years the young dig up, usually far away, wrecking surface towns and eating even huge subterranean monsters.

Nothing challenges it except its natural enemy and favorite meal, the gossamer noble, whose tentacles it shears off before using claws and jaws. Starving, it will crack starships for the crew inside, though wood and metal disagree with it. Gammaroids live for millennia, judging by growth rings on old shells, and a dead one's light, tough shell makes a nimble armored starship hull worth a king's ransom.