Ram's Horn Squid

Ram's horn squid, Spirula spirula, is a small deep-water, squid-like cephalopod mollusk, the only living member of its genus, family (Spirulidae) and order (Spirulida). Its common name refers to the shape of its small, coiled, chambered internal shell, which it uses to control buoyancy, and because the living animal bears a light-producing organ it is sometimes also called the tail-light squid.