Does anyone know what this black and white thing is on my live rock?

[Xyres]

It seems alive and like some type of plant as it keeps moving around and expanding every so often. Just not quite sure what it could be and I figured this would probably be the best place to ask as it looks reef like.

http://i.imgur.com/oxTMt.jpg?1?3683

[Leah]

Maybe a feather duster...hard to tell from the shot.

[Proteus]

+1

[mohammadali]

Maybe a feather duster...hard to tell from the shot.

feather duster doesnt move
it could be some type of anemone

[aquatechy]

feather duster doesnt move
it could be some type of anemone

i concur :)