I'm trying to identify this coral/sponge so I can label it in a video I'm working on. It was on the west side of Grand Cayman in about 50 feet of water. There was only one of them and it was maybe 18 - 24 inches in diameter. Looked like a big poppy and it was a pretty thing. Florent's Guide didn't show anything too similar. I don't know if it's a coral or a sponge. The second photo shows the fan next to it for scale. Who knows what this is? Some kind of disk coral?