Any idea what this is, it's on a rock with some Xenia and Anthelia, it's got tiny polyps like a montipora digitata and it's growing rather quickly, I've had it about a month and there were no spikes on it, as a matter of fact is was about a 1/2 in x 1/2 inch at the time, now it's at least double that size and it's starting to grow vertically.
http://www.canreef.com/photopost/sho...cat=500&page=1
Thanks, Doug