Cubozoa
Average Size – 10ft (3m) in length + the size of their body/box, which is usually another 8in (20cm)
The jelly/medusa form has a square or box-like bell, which is where their name, Box Jellyfish, comes from.
They can move somewhat quicker than other jellyfish due to their bell’s pulsation ability and have a more advanced nervous system as well because of the nerve ring around the base of their body.
Their tentacles are covered in nematocysts, which are loaded with poison and they have intricate eyes on each side of their box.
Most can be found in all warm coastal waters around the world, but the deadlier species tend to live in the Indo-Pacific or Northern Australia.
It is believed that they are active hunters and prey on shrimp and small fish. The reasoning behind this is their speed and advanced vision.
Some believe them to be the deadliest sea creature. Their stings have been known to pack a huge punch and can even be fatal, though not common.
They are capable of reaching speeds of up to 4.5mph and use this speed to actively hunt, in combination with their venom.
Box Jellyfish also called Cubozoa are a Class with over 50 species of Box Jellyfish.
The Australian Box Jellyfish are considered one of, if not the most, venomous marine animals. It is also the largest Cubozoa.