Is this a sponge?

[adurost]

Noticed this on my LR, does not appear to have grown much if at all in 2 weeks... Is it a sponge?

 

[reefforbrains]

Poke it with a finger. Is it soft?
Looks almost like Porieties from the picture.

 

[yosemite sam]

Are you talking about the white thing in the left-center of the photo? If so, I agree with Reefforbrains, it looks like a Porities skeleton.