white flower things in sand bed that hide when alerted

[esquire805]

Creepy stuff is this aiposia or feather dusters

[dkeller_nc]

Those are definitely not Aiptasia, which are a form of anemone. What you have are a species of feather duster, or possibly a barnacle. They're completely harmless, and at least in my opinion, a desirable creature to have in a reef tank.

[downbeach]

They do look like barnacles:

http://i1226.photobucket.com/albums/ee410/Downbeach88/barnacle_zps52fda642.jpg

[150Ron]

Not Aiptasia thats for sure. I agree with dkeller. No worries here they are harmless and a good addition.

[julie180]

Feather dusters. Good thing.