Tube thing with green tentacles ID

[tzptrans]

Just noticed these things and I am not sure if they are feather dusters, vermetid snails, some kind of aiptasia or something else. I recently moved this tank to another state, but nothing new has gone into the tank. Please help

 

[bradleym]

They look like hydroids. They can spread all over the rocks and become annoying, so unless you really like them I'd remove them.

 

[madmarks]

+1 Colonial hydroid