This is a snail…
Yuck. Snail is a common name for gastropod molluscs that can be split into three groups: land snails, sea snails and freshwater snails. Snails can have lungs or gills depending on the species and their habitat. Did you know that there are snails that can kill humans? The venom of a few larger species of cone snails, especially the piscivorous ones, is powerful enough to kill a human being.
Snail-like animals that do not have a shell are usually called slugs. Yuck. Did you know that they have 4 noses? That explains all of the snot or slime. While snails gross me out, they are quite important because they are an excellent food source for all sorts of mammals and beneficial insects.