What the heck is this? Is bad or benign?

[kalebos]

I recently was cleaning my tank and moving some frags around. I noticed underneath some of the frags there were some white/clear tube things growing. They don't move at all. I'm wondering if it is a sponge. Its hard to see the photo on the live rock, but if you look closely there are a few of them on the right side.

 

[sfin52]

Looks like a pineapple sponge first pic

 

[Double monti 61]

Probably dead now.

 

[sfin52]

Probably dead now.

Its fine. No worries about that.