Scorpions and brown recluse spiders are fine as far as they go, but if you want daily contact with venomous creatures, the ocean is the place to be. Blue-ringed octopi, stony corals, sea jellies, stonefish, lionfish, poison-fanged blennies, stingrays, cone snails, blind remipedes, fire urchins?you can choose your poison in the ocean. Venoms are often but not always defensive weapons. The banded sea krait, an aquatic snake, wriggles into undersea caves to prey on vicious moray eels, killing them with one of the world’s most deadly neurotoxins, which it injects through fangs that resemble hypodermic needles.