My first pest ID help!

[curtismaximus]

I have no idea what this is and have never seen it before. I havent added anything to the tank in about a month. Its about one inch long, clear looking and it looks like it has a piece of shell on its back. It has antennae like a snail but looks more like a slug or a snail that has had its shell eaten off.
Here are some pics: 1st with flash, 2nd without

http://i922.photobucket.com/albums/ad64/curtismaximus123/20130704_082237.jpg?t=1372335899" alt="" />

[IMG]http://i922.photobucket.com/albums/ad64/curtismaximus123/20130704_082252.jpg?t=1372335906" alt="" />

 

[clay4au]

stomatella snail, they are a good hitchhiker

 

[jimmystephens]

+1 no worries with these guys

 

[curtismaximus]

Well I panicked and took it out anyways! I didn't want to lose it and not be able to find it again. Then when I come back all my zoas are gone. Thanks for the ID though!