Weird Stick looking protrusions coming from my rock

[ChrisDowns]

Hello all,
So I have these strange little stick like things coming from my rock. I noted a few awhile ago and after doing a water change the other day I noticed that there were a good 15-20 more, and in places they weren't before. So I have some questions:
1. What are they?
2. Are they good or bad?
3. If bad ... how do I get rid of them?

*Sorry for the poor quality picture ... first time posting a pic here.

 

[StlSalt]

Vermetid snail. Common pest, not too bad they like to cast a web to catch food and that can irritate corals. There's tons of info about them and how to get rid of them if you want to.

 

[P-Dub]

The dreaded Vermetid! Crush, glue, epoxy, whatever you can to control them.

 

[homer1475]

+1
Vermetid snails

 

[Duffer]

Bubble bee snails took care of my problem

 

[Paul B]

I have thousands of them and I like them. They are normal, natural and fine.

 

[Sleeping Giant]