What is it?

[crohan]

I discovered two white feathery circles in our live rock and when I put my finger to the glass, one of them retracted. They are like little buds on the rock. Anybody know what they are?

[theplatypus]

Hard to say without a pic, but it's probably a feather duster.

[Loverotties]

Really need pic.Could be good,could be bad.

[aquawolf]

Take a look at this link and see if it is what you are seeing in your tank: http://melevsreef.com/id/tubeworms.html