what is this?

[svynx]

Hello everyone. I've done a little research on this and as far as I can tell, this is an encrusting sponge. It's almost iridescent, and film like, but tough. Am I correct? I'm trying to get rid of it as it is covering a nice pipe organ.

 

[Ron Reefman]

I don't know what it is, but I will say it doesn't look much like a sponge to me.

Hope somebody can help with a firm ID. Good luck.

 

[carrots]

I have something like that smothering my zoa patch. Looks like a typical sponge with all the vents, light grey in color but the outside layer is as hard as rock. I haven't been able to remove it due to it being attached to a large rock. Not sure what to do.