I wonder what this is?

[JSB]

I have these things growing on my overflow, near the bottom, well hidden behind the rock. The light is very low, so the photos are bad. They are pink/purple mound shaped, with a transparent tube pointing toward the surface. They are about the size of an oval quarter, and 3/16 thick. Some kind of tunicate, perhaps?

 

[Chameleon]

either a tunicate or sponge

 

[Dave3112]

I would say a type of sponge.

 

[skinz78]

Yep it's a sponge, they tend to like the dark spots

 

[JSB]

Well, they admittedly look spongy. Thanks. I just don't remember ever seeing sponges with the little proboscis looking thing.

 

[skinz78]

I actually got a clam in yesterday that has two different types of sponge on it, I'm hoping that they didn't get killed being taken out of the water with the clam in shipping.