Their liverock is loaded with cool stuff. I got some things I have no idea what they are but I like and are growing nice. I also got a couple trachyphyllia as hitch hikers from there, a cool green and red, and one all red. They had one that was about 5 or 6 inches around one day, I almost grabbed it but I was just low on cash.
As for your piece, I don't think it looks like a tunicate. I think it looks more like a chalice that grew around a few feather duster worms.