please help !!!!!!!!

[lostsoul1079]

ok i bought a piece of rock full of zoanthids on it well this small thing that i thought was a mushroom started growing....ive had the rock for about 5 months and now this thing is huge it looks like a mushroom with tenticals

 

[cloak]

Without a picture, it's kind of hard to say. A Majano anemone did come to mind first though.

Check this out.

http://www.lionfishlair.com/hitchhiker/hitchhiker.shtml

HTH.