The Sputnik Sea Urchin is so called because its arrangement of spines makes it resemble the Soviet sattelite Sputnik.

Sea Urchins are echinoderms, in the class Echinoidea. The spines serve as a defense against predators. Where Sea urchin predators are scarce, they sometimes reach plague proportions and have a devastating effect in a local area by consuming all the algae other animals depend on.

Whole Sputnik sea urchins are hard to find becase sea urchins usually lose their spines when they die, and are most often sold as bare shells devoid of spines, though spines are often sold seperately. In life the spines are movable in a ball and socket joint which decomposes faster than the shell and spines, causing the spines to fall off. In craft projects spines are often glued back on, and don't necessarily match the shell, reulting in a "morphology" unlike any living sea urchin.