Conus sp.

Found under dead corals during the day, coming out to hunt at night, over mud, gravel, and sandy areas, of coral and rocky reefs.

Conids have smooth cone shaped shells often very colourful.
They kill their prey by discharging their proboscis at great speed like a harpoon, then a venom is released and so paralysing their victim.
Extremely venomous to humans, may cause death, should not be handled.