What is this thing ?

[victor_peres]

Hello fellows,

In my live rock was appearing this this.
Anyone know this ? Is this reef safe ?
I have several these things in my live rocks.

Best regards,

 

[mscarpena]

I cant think of what they are right now, but they can irritate corals. If you want to get rid of them just break them at the base. They shoot out a mucus membrane to catch floating particles.

 

[Sugar Magnolia]

It's a vermetid snail. http://reefkeeping.com/issues/2005-01/rs/index.php