Sea Slugs are part of a Class of Mollusks known as Gastropods. These snail-like creatures do not use a shell for protection. Most Sea Slugs are a shade of green and have an elongated oval shaped body. These creatures usually have ruffled backs which uses increased surface area in order to absorb oxygen for respiration. At the head are tentacles that appear to be "rolled". Sea Slugs are algae eaters.