Fishing snail?

[MrSculpin]

Is there such a thing as a snail like thing, that sends out what looks like a line, then reals it in?
I have this odd thing in my tank, at first I noticed what looked like a hair flowing at the bottom of the tank.
Looking closer, the "hair" was being reeled into this tiny
tube. Next to the tube is what looks like a snail shell shape but it doesnt move. It might be just sitting next to the tube. Maybe Im seeing things!

 

[Herefishyfishy]

Vermetid snails feed by shooting small web-like mucus strings from inside their tubes. These are used to catch food. Considered a pest as the mucus can irritate other corals and are messy. Crush or poke with a nail, etc.

 

[eliterecon14]

I have some and they aren't that bad for my tank, i do have some things i have scraped off live rock for a teacher/friend. Like a majano anemone, chunked the rock and got it on a pebble and took it there.
They spread like wildfire and I have started to control some of them. The stuff looks nasty so i destroyed them.