At first glance, just a bit of long-dead coral. I was attracted more to the shadow than I was to the rock. I did notice the larger mollusk in the center when I photographed it. It was alive – I tried to see if I could remove it after taking the photo, and it was nicely suctioned in its place, happily protected by the coral. It was not until I got home that I noticed many, many other tiny mollusks living in the crevasses. Our coral reefs are precious beyond measure. And even long after it has died off, the remains of this coral colony have become a colony again.