What is this under my chalice coral?

[AnotherNewReefer]

Hi,

I got this chalice around 6 months ago and its been happy and appears to be growing slowly. A few weeks back I noticed something under it and it has been growing/extending since then.

Here are a couple pictures.

Can somebody ID what this is?

Thanks!

 

[mdb_talon]

Looks like sponge of some sort.

 

[afrokobe]

sponge, should be fine. But if it starts getting invasive, I would scrub it out. I had some sponges cover a zoa once.

 

[AnotherNewReefer]

Thanks! I will keep an eye on it to make sure it doesnt bother the coral.