Longest non-colonial animal (lion's mane jellyfish)

What to remember

The words "non-colonial" matter in this title. Some living things group together into superorganisms, as ants and bees do, and these are not classed as single large organisms. Among singular entities, the largest organisms on Earth are clonal colonies that can spread over large areas.

Once they are set aside, the longest animal is the lion's mane jellyfish, at 36.6 m (120 ft).

For comparison, the Great Barrier Reef, the largest structure built by living things, stretches 2,000 km, but it brings together countless organisms of many species. The jellyfish is a single individual.