Screwtape
Senior Member
Anyone have an idea as to what this is, I know picture isn't the greatest since I was in a hurry but this "invert" has built a tunnel like "shell" about the size of a quarter.
It then protrudes out and secretes some type of web which it then eats I think. I'm going to try and capture some video of this thing. I first noticed it on the live rock I bought back in November '09 where I thought it was some type of tube worm since it's "tube" stuck out from the rock. It's been growing but with it's shell parallel to the rock and doesn't see to cause any harm - it's pretty much stuck to the rock building it's hut.
Might be a type of vermetid snail. Usually harmless but the net/web they use to catch food can sometimes annoy corals.
