Sea Urchin (Spine-Caster)

These armored balls, roughly the span of a shield, bristle with thousands of needle-thin spines. They have no eyes; a crystalline organ-gem buried at their core grants an uncanny inner sight that lets them sense and target anything that draws near. Several breeds exist, told apart by color, from common black through prized silver. They creep over the sea floor grazing on shell-remains and carrion, rarely bothering larger creatures unless one blunders within a few feet. A hardy land cousin walks tidal flats on five spindly legs at surprising speed, hoarding pearls in its hollow body. Hunters seek them not for their flesh but for the gem and pearls within.