The shell of Cassis cornuta is a very popular collector's item, commonly called the Golden Helmet.
In some places the snail is hunted for meat and is traditionally roasted in the shell over fire. Because of both of these factors, humans are a major enemy, and the species is now at risk in many places. However, worldwide it is not listed as endangered.
It's an unusual addition to your nautical decor or shell collection.
This lovely shell is 9.5" wide on the bottom and 5.5" tall.