In my display tank I had a rock covered with 100+ Utter Chaos. After all were gone, then other Z&P's started to disappear. One night I saw an emerald crab feeding near some last zoas, so I decided to pull the rock out of the tank to see what I would find. I did not find the emerald crab but found this.... What is it? Is this what has eaten $100ssss of zoas? Please tell me your thoughts? This crab is now in my sump until I decided what to do.