Glow Shark, Glow!
The shy swell shark has remarkable tricks at the ready, especially its abilities to grow and glow. If threatened, it can turn itself into a sort of neck pillow, swelling up to warn off predators or prevent them from extracting it from a rocky crevice. It's also biofluorescent. Proteins in skin cells or other tissues absorb energy from sunlight and reemit it as a different color—in this case a ghostly green—under blue or ultraviolet light. How swell!
This nocturnal shark is common in coastal waters but also seen in depths up to 1,500 feet. It lives in the eastern Pacific, from central California to central Chile. Although primarily a solitary species, the swell shark can be found in groups, sometimes piled on top of one another.