Box Jellyfish are polypoid, free-swimming members of the phylum Cnidaria. Jellyfish are invertebrates, meaning they have no bones, exoskeleton, or shell to protect them. The majority of their body is made up of water. The water contributes to their physical support as they float through the water. The top of the jellyfish is known as the bell. Its shape varies. The outer layer consists of an epidermis. They have tentacles that grow out of the bottom and the sides. They are known for their electricity. Box Jellyfish are pale blue and transparent and bell or cubed shaped with four distinct sides, hence the name “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 meters in length with up to 5,000 nematocysts, also known as stinging cells. The Box Jellyfish shoots itself along in the water in a jet-like motion. The Box Jellyfish contains enough venom in one sting to kill a human, unquestionably.