Pyrosome

A pyrosome is a colonial tunicate made up of thousands of small individual zooids fused into a single hollow, tube-shaped colony that can stretch up to 20 meters long, drifting through temperate and tropical oceans worldwide. Each zooid draws in water and expels it through a shared central cavity, and the whole colony inches forward by combining every zooid's tiny jet of water, filtering plankton as it goes with one of the highest feeding rates known among drifting animals. Photobacterium bacteria housed in the zooids' light organs give the colony an eerie blue-green glow, the source of its name, drawn from the Greek for fire.