Box jellyfish
Although the notoriously dangerous species of box jellyfish are largely restricted to the tropical Indo-Pacific region, various species of box jellyfish can be found widely in tropical and subtropical oceans, including the Atlantic Ocean and the east Pacific Ocean, with species as far north as California ("Carybdea confusa"), the Mediterranean Sea ("Carybdea marsupialis") and Japan (such as "Chironex yamaguchii"), and as far south as South Africa (for example, "Carybdea branchi") and New Zealand (such as "Copula sivickisi").
Box jellyfish
Box jellyfish (class Cubozoa) are cnidarian invertebrates distinguished by their cube-shaped medusae. Some species of box jellyfish produce extremely potent venom: "Chironex fleckeri", "Carukia barnesi" and "Malo kingi". Stings from these and a few other species in the class are extremely painful and can be fatal to humans.