Jellyfish like the dreaded Portuguese man-of-war are also related to corals, but they’re part of a different subgroup, the siphonophores, which practice an unusual form of collective living.
Those who spend less time on the coast may not be able to recognize jellyfish as quickly. However, given there are over 2,000 different species of jellyfish, it's unlikely anyone is familiar ...
Jellyfish belong to a group called Cnidaria, which also includes sea anemones and corals. As animals, they are subject to the cycle of life and death - though one species is known to bend the rules.