Confession: Although I’ve owned many, I’ve never actually seen a sand dollar on a beach. I’ve always assumed that the pure white, delicate beauties that I bought in jars with other beach paraphernalia were just from more magical and majestic beaches than the ones I frequented. Beaches that instead of regular, old boring shells and rocks, are filled with the palest, softest sand that is dotted with the currency of the sea. It turns out, I’m an idiot because sand dollars aren’t shells or rocks or any other inanimate thing; the sand dollar is a living, breathing, moving creep of a creature.

So, what are they? Well, they are kind of like sea urchins and starfish! Sand dollars are part of the echinoderm phylum, like the previously mentioned sea critters, which are often recognized by the phylum’s signature radial symmetry. If you’re like me, the part of sand dollars you’re used to seeing is actually the skeleton. When you buy them in the store for decoration, they are usually bleached, but out in the wild they come in a variety of colors courtesy of their skin. Speaking of their skin, it’s covered in “velvety spines,” which in turn are covered by cilia—little hairs. As you can see in the videos, these hairs help the sand dollars move and are 100 percent disgusting.

Their mouths are in the center of the underside of their body, which is also gross, and they apparently eat plankton. Food is ferried to their mouths via cilia and once there, meets its doom in the form of the sand dollar’s five teeth, which chew food for up to 15 minutes. Another fun fact: when attacked, sand dollar larva (which looks nothing like adult sand dollars and is more of a tiny six-armed blob) clones itself. So there you have it, the sand dollar: a seemingly simple, innocuous sea creature that is actually a cilia-covered moral quagmire.