snail without shell?

[drunkintimmy]

so my lights have been off for awhile in the tank and the room its in because i was building a snowman lol anyways i came back in and i have something crawling on my rocks that looks exactly like a snail without a shell. is this possible or is it something else?

 

[newenglandreef]

stomatella probably.

 

[drunkintimmy]

looks like thats it lol thanks are they good to have or can they become a bad thing ?

 

[newenglandreef]

They'll tear apart your reef in one night. Just kidding. Friendly.