Hmmm looks like a Rhodactis or other type of mushroom to me..maybe a Discosoma? Do a google search for Discosoma Mushroom. I'm thinking that's exactly what it is.
It's not a type of mushroom but could be a enchinata but doesn't
look like the ones i have. The center area expands when i feed
and it has feeding tenticles. I'll see if i can get a picture of it
when it's feeding.