tank looks like its progressing nicely. See if you can get a more clear direct pic of that polyp may be able to help id. It may be a good species of soft coral. its great to get free corals with your rock. I get stuff like that all the time, I just got abot 25 purple mushroom corals on a 4.5 lb rock.
i highlighted where he is in the first pic i saw him in, incase i was unclear where i thought it was..
i agree about getting a better pic and making sure it isn't a free coral.. but if it comes to a close line i'd rather just nuke the little guy and have to spend $15 on a frag to replace it...
hotwater usually works but you have to make sure they are 100% DEAD!
peppermint shrimp work well also..
something like kalkwasser paste, joe's juice, or lemon juice injected INTO the nem works best but involves purchases...
BTW you name wouldn't happen to mean Luis (the name) CRX (the car by honda) would it?