The person that sold it to you probably has that other zoa in the tank and it just grew into that frag.
I believe that one is a Sunburst, I have the exact same ones. Those Bambams are gorgeous arent' they? I also got a frag recently and love them! It's cool when there is one or two different ones mixed into a frag, now you will have polyps of both of those!
-Gina