Most fish have no idea they’re about to be speared by a cone snail. The snail’s siphon hides a harpoon-like stinger, known as a radula, that extends and retracts in less than 100 microseconds.

Venomous cone snails attack their prey by shooting a cocktail of neurotoxins from a “harpoon-like barbed dart”, and can be found on beaches around the country, although the “deadly ones are ...