Spider-looking critters

[Satori]

Ed, I'm pretty sure the spider-like critters in my tank are Vermitid snails.

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

They have long thin threads of mucous streaming out, and when they "catch" something, they reel it in. Looks so much like a spider though. It's hard to see all the threads until I blow out the rocks and the debris sticks to all of them.

[Roll221]

Seems like an accurate ID, sound exactly what you described to me.

Ed

[Satori]

Mine don't have the "hatch" on the top of the tube, but like they say, there may be as many as 100,000 species of snails, so from what I've seen I'm confident they're a type of Vermitid.