"Just when you thought it was safe to go back in the water ..." 
So says the tagline used to advertise Jaws 2, and it rings a little too true after watching this video. What these divers recorded while swimming in Australia’s Tasman Peninsula might look like a giant tentacle monster, but it’s actually nothing to be afraid of. Apparently these long, glowing "worms" are called pyrosomes, and they’re made up of thousands of salps, otherwise known as "sea squirts."
Salps are marine invertebrates that move via jet propulsion, which involves pumping water into their bodies and pushing it back out. Scientists aren’t sure how these tiny animals are able to coordinate their behavior and move as one colony, but some believe that they communicate with light signals. For more information on pyrosomes, check out this article.