Things growing all over the glass?

I have had these things growing all over lower light areas of my glass and the acrylic in my refugium. These are the best pics I could get of one of the largest ones. They also were in my canister filter the last time I had it apart. They are very soft and have sort of feathery looking things coming out of the top. Ok, heres the pics thanks for any input.

 

It's either a scypha or leucilla sponge. Harmless. (in fact they are nice to have.....they absorb Silica and outcompete diatoms for this element)

 

Oh, very cool. They are spreading pretty fast. I think its kind of neat looking too.

 

Cool

 

So this tank is only about 4 months old so this came with my live rock I am assuming.