Need help in identifying

[geopod]

definately not harmful to the tank.They come as hitch hikers on rock you may have bought in the past.They are an anenome but they are ok.I cant remember the name.I have lots of them.Its not aptasia though those guys are nasty.I just had a bought with them and took me a few days to get rid of all mine.I burned them out with Kalk mixed with vinegar into a paste and injected the aptasia to get rid of it.