Resolved Unknown Coral?

I picked up a piece of cured live rock from a well established system. It is just full of living things... it actually makes me kick myself for getting dry rock sometimes. I'm nearing the end of my cycle and since I took it from one tank and put it straight in mine I was told it shouldn't hurt anything plus I'm still treating my water with a form of bio booster. Anyway, I have found all sorts of things on this rock such as asterina stars, micro feather dusters, snails, and brittle stars. I only see the brittle star arms and today I saw a whole one finally and they are all very very tiny except the one today, if it was spread out, was probably the size of a quarter. I can identify all of those... however today these opened up and I am guessing they are some sort of coral because they have a calcified base they attach to the rock with. I have no idea what they are because corals are my weak point because I've never had any at all. Luckily, I have a system that is capable of supporting corals now.

Anyway, anyone know what these are? I'm guessing since they are open and feeding that that is a good sign anyway.

 

kinda looks like a star polyp

 

+1 star polyp,

Saltwater Aquarium Corals for Marine Reef Aquariums: Starburst Polyp

it would be the coral towards the bottom of the picture.

 

cool, i have my green star polyps growing up the back side of my tank on the plastic. very hardy and but can sting other corals

 

Thank you all for the answers