secret of Box Jellyfish (Chironex Fleckeri)

Common names:
(class Cubozoa) are cnidarian invertebrates distinguished by their cube-shaped medusae. Box jellyfish are known for the extremely potent venom produced by some species. Chironex fleckeri, Carukia barnesi and Malo kingi are among the most venomous creatures in the world. Stings from these and a few other species in the class are extremely painful and sometimes fatal to humans.

box jellyfish description:
Box Jellyfish are pale blue and transparent and bell or cubed shaped with four distinct sides, hence box jellyfish.
Measuring up to 20 cm along each side of the cube or bell, the Box Jellyfish  has up to as many as 15 tentacles on each corner which can be 3 metres in length with up to 5,000 nematocysts (stinging cells).
The Box Jellyfish shoots itself along up to speeds of 4 knots in a  jet-like motion.

Killing technique:
The Box Jellyfish's Lethal Venom
     The sting of a box jellyfish causes excruciating pain and skin damage and can leave permanent scars. In severe cases, death may occur from heart failure or drowning following loss of consciousness. A box jellyfish antivenin is available in Australia. In northern parts of the country, some beaches are closed to the public for periods between November and April when the jellyfish are most abundant.