interesting thing

Yep, Ball tip Anemone.
I had one about a year ago and tried to get rid of it since it almost wiped out my entire colony of pink Palys when it decided to walk along the rock they were on. Scraped it off of the rock, but must of missed a VERY, VERY small piece of it. About a month or so later, it was back in the same spot (no pink Palys were near it anymore). I decided if it wanted to live that badly, then so be it, so long as it didn't go near anything else. It's been in my tank ever since, moving once, and it's never bothered anyone or anything since it moved to it's new spot (all alone and away from everything else). Actually kind of cool looking, so I'm glad I still have it. As long as it doesn't sting anything else, it can stay.