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.
Carybdea branchi
This small box jellyfish grows up to across and may have tentacles of up to in total length. It has a transparent box-shaped bell with a very long tentacle trailing from each corner.