Another what is this?!

[isuguy]

I found this guy usually early mornings out and about with the lights off, but saw him out and about during the day for the first time today. He's definitely not something I bought and when I moved the scrubber around to see what he would do (cuz I was actually gonna clean it off), the thing shot out 3 or bursts of white stuff. My tank is about 6 months old. Anybody know what it is?? Good/bad/neither? Mixed reef tank

 

[Sugar Magnolia]

Harmless stomatella snail, great little cleaners.