Help! Identity unknown

[itsgoochy]

Not entirely sure what this is growing next to my mushrooms in my 29g bio cube but any help would be appreciated! I noticed it when I chipped a piece of rock off that had aiptasia

 

[itsgoochy]

Sorry for the pic quality but it's black and in a darker spot in my tank!

 

[itsgoochy]

A little better shot of it here

 

[JMSKI333]

Looks like some sort of sponge. Is this live rock we are talking about?

 

[itsgoochy]

Yes live rock. I bought the rock about 2 months ago with about 10 mushrooms and Xenia attached.. Since then about 3 more mushrooms have shown up and everything seems to be doing well. Just noticed this black stuff when I took the rock out to remove an aiptasia bud

 

[JMSKI333]

Yes my guess is it is a sponge of some kind in which case it is harmless. Maybe someone else will help confirm that for us.

 

[Tahoe61]

Perhaps Liver Sponge.

 

[NewEnglishMutt]

It's a sponge,

. And it'll grow