Is this blue coralline?

[John Wassman]

I got this on a rock that my devils hand was attached to. It was a small spot but now has grown relatively large about the size of a quarter. Stayed this bright blue color the entire time. It has transfered to some of my existing rock. I do not have it anywhere else in the tank. Anyone know what it is?

 

[tdileo]

probably a sponge

 

[reef lover]

Sponge very pretty.