When Bill Bailey guesses the longest animal in the world to be a Portuguese Man O War, Stephen Fry awards him ten points for guessing a type of jellyfish, albeit not the correct type.
However; the Portuguese Man O War is not a jellyfish, it is a siphonophore. It is also not a single animal. Like all siphonophores, the Man O War is a colony of organisms performing different functions and living as one.