What could this be?

[jimbo24]

I bought a live rock a year ago from the lps.. It had like 10 bright green and purple mushrooms... I was a newbie then so i didnt take care of my tank to well and they died off
I was recently moving around rocks and found this on it
I do remember seeing this on the rock when i first got it
well something similar i remember them in a different spot
Is this glue? its very soft to the touch, More mushrooms
Both of them have a tiny pin hole kinda like a feather duster

 

[joy13]

I see what I think is a sponge and a feather duster.

 

[JoshuA c]

I agree with above

 

[jimbo24]

yes feather duster in the back
what kind of sponge could it be?

 

[JoshuA c]

It may just be one that hitchhikes and grows a bit on the rock, not one you can normally buy. It's just another filter, if it is a sponge, keep it.