Invasive species?

[xelios]

Hi guys I was wondering if any of you have seen this before it seems to have been growing all over my corals when opened it looks like a feather duster. Is it a nuisance?

[/IMG]

 

[cloak]

Those look more like Vermetid snails IMO.

http://www.reefkeeping.com/issues/2005-01/rs/index.php

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