I recently purchased some new live rock from an established aquarium and I think I may have bitten off more than I can chew. What I mean is that I received quitea few hitchhikers including baby brittle stars, bristle worms, mushrooms and a small shell with what appears to be a polyp with tentacles sticking out of it. It seems to have moved but it could also be the current in my tank because it hasn't gone very far. I looked up pictures but I can't figure out what this thing is or how to care for it. Please help anyone have ideas? I have a really good picture of it but I only have my iPhone an can't figure out how to upload the picture! If anyone thinks they might know what this is I will be happy to email it to you directly! Thanks for your help!