Identification of....something growing in my sump

[21reefstreet]

I have something growing in my sump and need help identifying. I was cleaning my sump and noticed these guys all over. Looks like small cotton balls with a small tube or something coming out. They are in the sump but not the display tank. Any ideas...and are they harmful. Not the best picture, but the best I could get.
Thanks

 

[AdamD76]

harmless filter feeder.

 

[KJ]

Pineapple sponge.

 

[21reefstreet]

Filter feeders?...I like them already.
Thank you for the help