Anyone know what this is, or seen it before?

A while back I bought some Aussie orange zoas with some of this brittle purple stuff on the rock. I assumed it was dead, but left it attached. It was such a bright purple I thought it was coralline covering something dead. Now, about 6 months later, its grown into a little bush. It feels cartilaginous... kind of between brittle and bendy if that makes sense.

It's pretty, and grows a heck of a lot faster than the zoas it came in on. I was just wondering what to call it; "coralline bush" doesn't seem fitting.

6 months ago I didn't realize it was going to grow so I don't have a great starting picture
Aussie Orange Zoas top down 07-04-10.jpg

Now:
Purple Macro 8-24-10.jpgPurple Macro 8-24-10 Closeup White Light.jpgPurple Macro 8-24-10 Closeup Blue Light.jpgPurple Macro 8-24-10 macro shot blue light.jpg