That's a tiny sea mollusk called a chiton, that lives about 50 feet below the water's surface. It's a pretty darned weird animal, but scientists have found something that makes it even more remarkable: it has eyes made of rocks.
"Turns out they can see objects, though probably not well," said study researcher Daniel Speiser, who recently became a postdoctoral fellow at the University of California, Santa Barbara. [...]
The team realized in a lab experiment that the animal's lenses were made of aragonite (calcium carbonate), rather than proteins like other biological lenses.