Alex Mustard / Planktonic pyrosome, drifting in blue sea. Ras Mohammed National Park, Sinai, Egypt. Red Sea

Doug Perrine / Pyrosome, a type of pelagic colonial tunicate known for its bioluminescence, photographed at night, Kona, Hawaii, USA.

Pascal Kobeh / Pyrosoma / sea tunicate (Pyrosoma sp) in the open water at night, Palau, Philippine Sea

Aflo / Colonial tunicate (Pyrosoma spinosum) Komodo National Park, Indonesia.

Richard Herrmann / Salp (Pyrosoma sp), San Diego, California