Its hard to tell from the pic... but it doesn't look like that middle spire has a growth tip. So it appears to be some sort of encrusting montipora. It doesn't have the structure of an undata which has a much smoother appearance and lacks those spires and nodules around the leading edge. I'd guess its a type of peltiformes or possibly nodosa from the growth pattern? No idea though for certain... I've never seen bright teal polyps like that on a montipora other than an undata.
Regardless, its a nice specimen. The guys on reefcentral might have more of a clue.