As if sharks weren't terrifying enough, new studies have found that to overcome being seen in open water, certain types of sharks have learned to become invisible. Light trickery allows for these "invisible sharks" to emit something akin to an optical illusion--supposedly 50 species of sharks are able to emit light from their bodies.
One invisible shark in particular is named "the phantom hunter of the fjords," which--frankly--sounds horrifying. The sharks usually omit the light from their bellies, and the light can be changed and altered if the surrounding lightening is changed. These invisible sharks are not using their light trickery for human pray, thankfully.