weird stuff on my ricordia rock

[foxface]

Anyone know what is in these tubes?
From what I can see, it looks like feather duster tubes with some strange little creatures in them. They let out some kind of buggers into the water and then a while later they slowly pull it back in. You can see in the pic the fan of snot connected to the pointy nosed little guy in the tube.
Also, can anyone ID the smooth gray coating on the rock? It feels slippery and has small bumps everywhere.
Louise

[rj593]

Looks like a vermetid snail - http://www.reefs.org/library/aquariu...97/0897_8.html

They will excrete a web of mucus to filter the water then retract it to feed on the particles that were collected.
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HANDJOB PUBLIC