I'm a big advocate of using fire to solve many problems. Too bad everything reeks after the torching of the rock.

Torching Aiptasia
 

After reading Myka's post and after a quick internet search, I found out I not only have aiptasia but also majanos. I have decided that I am going to run an experiment and try a few methods. I have a hypodermic needle and syringe, from my past life as a farmer. I shall stab some ... fry some ... and shrimp some!

Torching Aiptasia
 

Another method I think that I will try ... manual removal of the lil brats and do a quick pass with the torch. This should (?) limit the damage to the rock. I will then give the area a good scrub with a toothbrush. I will be so good at removing them people will call me the nem whisperer LOL!

Go get a small copper band buterfly, they are awsome at eating them. Solved our ap. issue. We had hundreds, look up our old post's for the pic's.

Here's what I did when I bought some xenia that was attached to a mushroom covered rock. Saw one of these pesty buggers coming out of a hole in the rock a couple of weeks after I placed into the tank. ( I had dipped the corals with Revive for about half an hour first, to make sure any other bad hitchhikers didn't survive) Lo and behold, one aptasia survived and started sprouting out. I've heard many different remedies on how to deal with these buggers. Didn't have any Joe's Juice that night, but I remembered some people used vinegar or lemon juice. Also remember reading that others used some form of heat, like hot water or blow torches. Not wanting to take the rock out of the tank and maybe damaging the corals, I opted to use boiling hot white vinegar. Just heat a little in the microwave and inject it into the aptasia with a syringe. The bugger shriveled up and died immediately.Basically I was using hot acid. Best of both worlds, and free.
Since then, have never seen another aptasia in my tank.

You were lucky because they are very difficult to keep alive.
There was a recent post on this.

There are so many options to remove them that it doesn't make sense to get a copperband butterfly unless that is a fish you want to keep anyway.