I saw a white shell less snail or slug too. I saw him on glass at night and move very quickly could that be a slug. I should of took a picture too. If I see him should I remove him or keep him. About 3/4"
Without a pic it hard o say but I'm pretty sure you guys are talking about stometella snails. Google the name, there are a ton of pics. And yes they are harmless and excellent lil cleaners.