Praya dubia

Praya dubia or giant siphonophore is an invertebrate, a siphonophore that lives in the deep sea at 700 m (2,300 ft) to 1,000 m (3,300 ft) below sea level. It has been found off the coasts of a rapidly-growing list of nations around the world — 19 countries so far, from Iceland in the North Atlantic to Chile in the South Pacific[1] — thanks to advancements in deep-sea submersible technology.

Praya dubia is a member of the Hydrozoa class with a body length of up to 50 m (160 ft), the second-longest sea organism after the bootlace worm. Its length also rivals the blue whale, the sea’s largest mammal, although Praya dubia is as thin as a broomstick.[2][3]

The giant siphonophore is not a single, multi-cellular organism, but a huge colony of tiny biological components called zooids, each having evolved with a specific function. These zooids cannot survive on their own,[4] relying on symbiosis in order for a complete Praya dubia specimen to survive.