A hunting snail with a harpoon, and the one animal on a muck site that should never be picked up.
A smooth conical shell to about 15 cm, patterned in browns, oranges and whites, usually with the animal buried and only the siphon showing by day. Several dozen species occur across the region and they cannot be sorted by eye into the dangerous and the harmless. This entry covers the genus.
Cone shells hunt with a modified radular tooth fired like a harpoon on the end of an extensible proboscis, which can reach any part of the shell including the end a hand would hold. The fish-eating species carry a venom that acts within minutes; human deaths are documented, there is no antivenom, and treatment is pressure immobilisation and supported breathing until the venom clears. The practical rule is the general one for muck diving stated more firmly: nothing is picked up, and a cone shell least of all. Watching one hunt at night, which it does by extending the proboscis across the sand, is worth more than the shell anyway.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.