Yes it is fun. Well, as long as we figure it out I should say. lol
I thought of the lobophyllia and actually have seen a couple symphillia that looked very much like it. I am not sure about the mouths though, as it doesn't eat with the lights on and I didn't think to check for mouths. Next round of feeding, I will have to see if I can make out any. Now, when the lights go out though, it has feeders and sweepers that come out all over it though and it looks very cool. It makes me think all the ridges/rings are surrounding mouths. Oh, and it definitely likes the shaded part of the tank for sure.
We started with it where it is in the picture, but we moved it due to some rock flower anemones making their claim to that location (hence the sexy anemone shrimp all over it) and the wife (it is her nano tank by the way) didn't want to find out who would win that fight. My money was on the RFAs, as there are 4 of them, but I kept telling her, you never know. We could be surprised - nature can often be unpredictable. lol
Well, the new location is a more open shaded spot, almost like a large cave and, despite the fact we have only had this guy for a little over 2 weeks now, it looks like it has grown since we moved it! Plus, when the lights go out, you can see it seems to love the slightly lower waterflow. It's feeders aren't stretched out as far.
I also thought of the acanthastrea bowerbanki, but we got one of those when we got this guy, and they don't look even remotely close to each other. I didn't think about a favia though, he seems bigger than the favia I've seen. Although, I haven't kept any favia and I am definitely not an expert. That's why I came here.
Thank you for the input, I am very interested in what other ideas/suggestions we get on this one.