Chironex Fleckeri
C. fleckeri, a member of the Chironex genus, is a species of box jellyfish, and is one of the deadliest creatures in the world. It is also known as the sea wasp. Like all cnindarids, it has no skeleton. C. fleckeri is the largest of the cubozoans (collectively called box jellyfish), many of which may carry similarly toxic venom. Its bell grows to about the size of a basketball. From each of the four corners of the bell trails a cluster of 15 tentacles. The pale blue bell has faint markings; viewed from certain angles, it bears a somewhat eerie resemblance to a human head or skull. Since it is virtually transparent, the creature is nearly impossible to see in its habitat, posing particular danger to swimmers. C. fleckeri is best known for its extremely powerful and occasionally fatal "sting". The sting produces excruciating pain accompanied by an intense burning sensation, like being branded with a red hot iron. In Australia, fatalities are most often caused by the larger specimens of C. fleckeri.