Unknown Blue Alge on my coral - What is it?

[WarriorPriest]

Hello,

I'm wondering if someone can identify this blue Alge which is growing around and on my coral. It's very strange looking and feels rubbery when I touch it. I removed the coral from the tank. On the coral and live rock shown in the photo is the only location in my tank that I see this stuff. It appeared in the tank or I first saw it about 1 month ago. My water chemistry is testing good. Please check out the photo. Any help is appreciated.

 

[joshky]

Not algae, but a blue sponge.

 

[phobos2deimos]

Very cool sponge. Also a sign of good water quality.