Also known as Bonnet Snail, Grey Bonnet Snail, Helmet Seashell, Helmet Shell.
Found buried in the sand during the day close to dead coral areas over exposed reef flats coming out at night to feed over lagoons, coral and rocky reefs
They feed nocturnally on sea urchins.
Length - 14cm
Depth - 0-10m
Widespread Indo-West Pacific
Cassidae can grow very large and their shells resemble Roman Helmets. These are sand dwellers mainly hunting sea urchins such as sand dollars, using chemicals to penetrate through the hard case via the anus or by drilling a hole. Ref: https://en.wikipedia.org/wiki/Phalium_glaucum