Chiropsalmus quadrumanus
Chiropsalmus quadrumanus, commonly known as the four-handed box jellyfish, is a species of box jellyfish found in the western Atlantic Ocean, the Gulf of Mexico and the Pacific Ocean. The sting is venomous and dangerous to humans, especially children.
Box jellyfish
Although the box jellyfish has been called "the world's most venomous creature", only a few species in the class have been confirmed to be involved in human deaths, and some species pose no serious threat at all.