What is a box jellyfish?

The Australian box jellyfish is considered the most venomous marine animal. Craybdea branchi, pictured here, is a relative of the Australian box jellyfish (Chironex fleckeri), which is considered the most venomous marine animal. read more

A fully grown box jellyfish can measure up to 20 cm (7.9 in) along each box side (or 30 cm (12 in) in diameter), and the tentacles can grow up to 3 m (9.8 ft) in length. Its weight can reach 2 kg (4.4 lb). read more

Box Jellyfish View Images The box jellyfish's venom is among the most deadly in the world, containing toxins that attack the heart, nervous system, and skin cells. read more