The box jellyfish (
Chironex fleckeri), also known as the
deadly sea wasp, is the the world's most
venomous marine creature. It is usually found in
shallow waters off the coast of northern
Australia.
The bell of this lethal jellyfish is box-shaped, and is often as large as a basketball. At each corner of the box is a bundle of ten to sixty stinging tentacles, sometimes two meters in length. Although this jellyfish is quite large, it is near-impossible for humans to see while underwater, thanks to its translucency and relative immobility. The tentacles are covered with approximately 5,000 nematocysts, stinging cells which are activated by chemicals on the surface of fish, shellfish and humans.
Adult box jellyfish spawn at mouths of rivers during late summer (keep in mind this is around March in the Southern Hemisphere). Fertilized jellyfish eggs stick to rocks, and eventually grow into little jellies which migrate downstream. These primitive sea creatures actually have some things in common with us: they like to eat shrimp, and they like the same kind of beautiful beaches that humans like. They are passive hunters, remaining still and hoping that prey bump into them. The jellyfish's extremely powerful poison is necessary for its way of life, since a pissed-off shrimp can actually do quite a bit of damage to the jelly unless properly subdued.
The deadly venom isn't the only interesting fact about chironex. The jelly can see through four eyes, one at the center of each side of the bell. Yet, it has no brain to process visual information, and scientists aren't exactly sure how it is able to see. It is a very shy creature, and tries to avoid contact with any objects that it doesn't prey upon. Thus, the 70+ human deaths attributed to the jelly are mostly the human's fault for bumping into the acaleph. Not all animals fear the box jellyfish; turtles, unaffected by the jelly's sting, like to eat them.
If you happen to bump into one of these creatures while going for a swim, you're in for a seriously ardiotoxic, neurotoxic and highly dermatonecrotic experience. The venom almost instantly enters your bloodstream. Coming in contact with about three meters worth of tentacle will likely render you a floating carcass. If you're not too paralyzed by the excruciating pain, you'll notice that the activated tentacles are rather sticky, and are very difficult to pull off. In addition, attempting to remove the tentacles from your skin is a good way to exacerbate the sting and kill yourself. Perhaps the best thing to do is realize that a large portion of your skin is already dead and hope that the scared jelly lets go REAL SOON. Resign yourself to the fact that you are going to be in extreme pain for weeks, and that you will one day be able to show your grandchildren your huge scars.
If you have vinegar handy (I know I never swim without it), you might want to pour some over the tentacles, to inactivate the nematocysts. Then the tentacles can be removed in a less deadly manner. It's important to note that you will still be in the worst pain of your life, and that the vinegar is not intended to alleviate the suffering or stop the poisoning; it just stops things from getting worse. Should respiratory or cardiovascular failure occur, routine first aid such as CPR, artificial respiration, or cardiac massage might be advisable. If the paramedics don't have the antivenom with them (ouch!), they'll immbolize your limbs until you get to the hospital.
Administration of the antivenom will reduce pain and decrease scarring, provided you are treated relatively soon after the nasty sting. While you lay in the ambulance covered in lesions and going through cardiorespiratory arrest, you'll notice that it is very difficult to breathe or swallow. As the paramedics give you analgesics and ice packs, count yourself lucky to be alive after an encounter with the world's deadliest swimmer.