#sea snail

I found this baby snail looking/slug in my tank. It has a hard shell on the outside, but his body is way larger than the shell. Wondering if this is a smell that was just born and hasn’t grown at shell. Or is that a sea slug? I have multiple Snail species in my tank If it is recognizable to...

I had has this sea shell for a while and I’ve just started to wonder what kind of sea shell is it because it looks like a sea snail shell also how rare it is? Look at the images below.