The marine snail group that uses a harpoon-like radular tooth to inject venom is the cone snail.
Cone snails are venomous predatory sea snails in the family Conidae. They use a specialized tooth from their toxoglossan radula, a chitinous feeding structure, as a disposable harpoon. The tooth is loaded with venom and launched from an extendable proboscis into prey such as marine worms, molluscs or fish.
Their venoms contain conopeptides, short peptide toxins that can disrupt nerve and muscle signaling. Fish-hunting species may release a cloud of venom before striking, while worm-hunting species commonly sting and retract the prey. A few large tropical species can seriously injure or kill humans, especially when handled.
Limpets, abalones and cowries are also marine gastropods, but they do not use the distinctive venomous harpoon system associated with cone snails. Cone-snail venom has also inspired medicine: ziconotide, a powerful pain drug, was derived from a toxin of Conus magus.