Slugs are fairly common on Mackinac Island. Big slimy leopard slugs that can be up to six or seven inches long.
I often see them trying to cross the road on damp mornings during the summer months. (The squished ones are really gross.)
I found this one crossing my yard on his/her (slugs are both - they're hermaphrodites) way to have a snack in my garden. I relocated it to the back of the empty lot across the street where it can nibble on the greens to its heart's content. I'd rather it not munch on my flowers.