I have a button polyp that shared living quarters on a piece of live rock when I bought another coral. I initially thought, wow. Two for one! Then, I noticed, over the next few weeks, that they had detached themselves from the original piece and started growing all over the tank. It's a bit late to try and kill them off one by one, as it would be a lost cause I think. I don't have a pic of it, but it looks remarkably like a button polyp, but the fingers are chubbier. Color is a hue of purple, with a central dot (just like a button polyp). It attaches to anything, even other corals! ARGH!!! Any ideas? I am sure it isn't Aiptasia.