Not a snail...? What is it

[EnemyAnenome]

Is this little guy good or bad for my tank? Looks like a snail with no shell? He recently popped up out of nowhere. Let me know if the videos aren't working I'll resubmit them as a jpeg

 

[Soren]

Is this little guy good or bad for my tank? Looks like a snail with no shell? He recently popped up out of nowhere.

Stomatella snail, considered very beneficial clean-up crew in every case I've read about.