This is a Portuguese Man 'O War, also known as a blue bubble or blue bottle. While many people think that they are jellyfish, they are actually a colony of different kinds of specialized creatures, all living together. Some of them produce the gas that fills the float. Other individuals specialize in propulsion, predation, digestion, or reproduction. individuals are so specialized that they cannot survive on their own, making the Portuguese Man 'O War one of the most complex colonial animals.