Tree Stump Looking Thing On Live Rock

[maryd]

I have a growth (?) on some live rock which resembles a tree stump, it's soft to the touch and brownish in color. I did not find anything like this in the hitchhiker thread. I dont' know if I should remove it or keep it? It is slightly larger than a quarter and sticks up about half an inch.
I don't have a digital camera yet so I can't post a photo of it.

 

[ouchthathu]

It could be either a polyp or a sponge, I wouldn't be able to tell without a photo.

 

[maryd]

I don't think it looks like a sponge. I have some of those on live rock. It really resembles a tree stump, same look. But it's soft to the touch. I read something in one of my books about Murex or something like that.