7. Cone Snail
Found in the warm waters in the tropics, these beautiful creatures—instantly recognizable for their highly prized brown-and-white marbled shells—can be seen in shallow depths closer to shore, near coral reefs and rock formations, and beneath sandy shoals. But do not dare to touch the 4- to 6-inch long gastropods: their concealed, harpoon-like “teeth” contain a complex venom known as a conotoxin, making them one of the most venomous species of snails. If you suffer the unlucky fate of becoming one of the handful of people ever stung, head to the emergency room immediately, as there is no antivenin. The toxin stops nerve cells from communicating with one another; so the creature not only causes paralysis within moments, but, per its nickname of “cigarette snail,” affords you about enough time to smoke a stick before you die.