I am a gardener and snails are very plentiful in my gardens, but not the spiral shelled ones in your drawing and photos. I'm convinced the ones I have are slugs that grew shells so they are more sun tolerant and can do damage all day long. They're brown, their shells are elongated and they are far less attractive than the ones in your post, (especially your snail sketch. He is adorable!)
Maybe he's worried about whatever it is he's looking at. Idk but that's my take for what it's worth. It would be up to the creator to supply what that might be...
They are terrible pests in a garden. Both snails and slugs!