Need help identifying

[Bignasty1]

I have some growth on one of my rocks. It kinda looks like some kind of algae but I am unsure. I read some articles today that might lead me to think it is bad. Can I get some help identifying what this could be. What I am referring to is top left of the coralline.

 

[Tomoko Schum]

It's hard to tell from the picture. I see some sponge like things below it. What's that dark blue thing sticking out above it?

Tomoko