Box jellyfish

Box jellies are water-dwelling invertebrates belonging to the class Cubozoa, named for their cube-shaped medusae. They share many characteristics with their relatives the true jelly in the class Scyphozoa. The name sea wasp is also applied to some species of cubozoans, including Chironex fleckeri and Carybdea alata.

Box jellies are found in Australia, the Philippines, and many other tropical areas. They are known for the often-fatal effects of their venom, although not all species are dangerous to humans. One box jelly species is the most venomous species in the world.