Ok I don’t want to be one of those guys but this one here has me stumped. This is on rock that have been in my tank for almost 5 years now. I have never noticed or seen this before until I upgraded my tank and moved the rock over. It almost looks like an encrusting sps but it is in a very little light area. When I first moved the rock over it was just a small little patch growing between the sponges. It is now growing over the sponges growing on the rock. It looks like it has brown polyps with a green base. At first I thought it might be some of the ORA Spongodes growing above it but it is not the same. So what is it?