I found this neat gastropod while tidepooling in the San Francisco Bay Area. The Angular Unicorn is a type of predatory snail found on the intertidal zones. Its shell exterior varies from gray to yellowish-white. Several white spiral cords, with dark interrupted grooves between, encircle the shell.
The Angular Unicorn belongs to the mollusk Family Muricidae, a large and varied group of small-to-large predatory sea snails, commonly known as Murex Snails or Rock Snails.
It is found on protected rocks and pilings in the high to mid-intertidal zone and its range is most of the California coastline. I found these in plain sight, hanging out on rocks during low tide. They eat barnacles, mussels, snails and other types of invertebrates. Often times, hermit crabs utilize their shell once the snail dies.
When this snail finds its prey, it attaches itself to its prey’s shell. Then it produces hydrochloric acid, enzymes, and other substances to soften the prey’s shell. Once soft, they rasp it away with their radula (a structure of tiny teeth), thus creating a characteristic hole.
After breaking through the shell, the Angular Unicorn sticks its mouth inside the clam, barnacle or snail and, using its radula, rasps away the clam’s tissue, basically eating it alive.
This species gets its “unicorn” common name from the little pointy projection that it has at the front of its shell.