Not sure what is on my zoas

[Joeanzo]

So I just noticed what appears to be a spider web around the base of my zoas and I know people posted something similar but this is different looks like an a actual spider web any help would be greatly appreciated

 

[Mr Fishface]

Looks like a sponge that used to grow in my tank too, near my green mushrooms.

 

[reef lover]

+1 sponge