Spirula

Spirula is a genus of deep-water, squid-like cephalopod mollusk containing a single living species, Spirula spirula. It is the only extant member of the genus, the family Spirulidae and the order Spirulida. Because of the shape of its internal shell, it is commonly known as the ram's horn squid or the little post horn squid, and because the live animal has a light-emitting organ, it is also sometimes known as the tail-light squid. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/