When you're stung by a box jellyfish, you know it almost immediately. These somewhat squarish shaped cnidarians are armed to the bell with some of the most painful venom in the world. Long tentacles are packed with millions of stinging cells, called nematocysts, each with its own microscopic, needle-like harpoon-tipped tubule waiting to plunge into your flesh and inject the animal's intense venom. The pain is not only debilitating, it can also be deadly. More than 60 deaths from box jelly st
