Chiropsalmus quadrumanus
Chiropsalmus quadrumanus, commonly known as the four-handed box jellyfish, is a species of box jellyfish found in the western Atlantic Ocean, the Gulf of Mexico and the Pacific Ocean. The sting is venomous and dangerous to humans, especially children.
Box jellyfish
In Australia, fatalities are most often caused by the largest species of this class of jellyfish, "Chironex fleckeri". Researchers at the University of Hawaii's Department of Tropical Medicine found the venom causes cells to become porous enough to allow potassium leakage, causing hyperkalemia, which can lead to cardiovascular collapse and death as quickly as within 2 to 5 minutes. It was postulated that a zinc compound may be developed as an antidote.