help with a snai ID

[Jack]

Well, something after all survived on my live rock, lol.

This is gonna sound dumb, but for a guy that hasnt had live rock yet, help me out. I found a white snail this morning when I woke up and turned on the lights. He is about the size and shape of the lead part on a sharpened pencil. He is cruising along my front glass, hes alive and well. He is white and the shell is spiraled and long.

What is this? Is it bad or good? Am I just freaking out about nothing?? Thanks