Sponges?

[bounchak]

Hi! What are these growing on my live rock? The big tan/grey thing just grew a tube like thing in last few days.

 

[thomas_neil]

Hi! What are these growing on my live rock? The big tan/grey thing just grew a tube like thing in last few days.

Looks like vermetid snail.

 

[ying yang]

I would say looks like a feather duster/ tube worm tube but....
Do you see a mucus net coming g out of it catching food and dragging back in ( vermitted snail)
Or see a feather like thing coming out tube and reacts to light / shade or if go close to it ( feather duster ) and sponge is the white / grey thing of some kind I would say