The giant siphonophore is a deep sea cnidarian that can grow up to 50 m long. However, it’s long body is not a single multicellular animal, because each segment of its body is an individual organism. The chain-like formation the segments arrange into is known as a physonect colony, and an individual segment in the chain cannot live on its own. The siphonophore actively swims at depths up to 1000 m, where it uses bioluminescent light to attract prey and then paralyze it with its stinging tentacles.