Id Please

[tripleshot]

Could someone please tell me what this is? Last week i bought this ricordia mushroom rock. And in between the two peices of rock as you can see in the pic. Their is this yellow tube like thing. I know it is a filter feeder but dont know what kind.. Sorry the pic isnt the great but had to take when the lights are all off. Otherwise it is hard to see when the mushroom is open above it. thier were about 7 different types of things on this one rock. Will try and get more pics of the stuff on it that i dont what it is. Here is a pic of my open brain coral with all the little tentacales out.

 

[schadiest1]

could it be a type of sponge?

 

[thomas712]

It could be a sponge, but from the pic I don't see any so called port holes coming from it. That could be because the rock might have been on the substrate on that side.
Thomas

 

[tripleshot]

It does have a opening at the front and at the back that opens and closes when feeding. It will also close breefly when lights come on.