Pyrosoma atlanticum is a pelagic species of marine colonial tunicate in the class Thaliacea found in temperate waters worldwide. The name of the genus comes from the Greek words pyros meaning 'fire' and soma meaning 'body', referring to the bright bioluminescence sometimes emitted.

Pyrosoma atlanticum has a tough, bumpy texture, gets up to 60 cm long (but may be much smaller, and has been described as pickle-shaped), and is colourless or tinged with a bit of blue, grey, yellow, or pink. This is the most common pyrosome worldwide.

The scientific name of the species found on Morro Strand this August is Pyrosoma atlanticum. Which roughly translates to “Atlantic fire body.” The “fire body” part of their name comes from their ability to give off light from chemical reactions in their bodies, a power called bioluminescence.