
Turritopsis dohrnii, a potentially "immortal" jellyfish species that can age backward, is silently invading the world's oceans.
Like the Brad Pitt movie character, the immortal jellyfish transforms from an adult back into a baby, but with an added bonus: Unlike Benjamin Button, the jellyfish can do it over and over again - though apparently only as an emergency measure.
About as wide as a human pinky nail when fully grown, the immortal jellyfish (scientific name: Turritopsis dohrnii) was discovered in the Mediterranean Sea in 1883. But its unique ability was not discovered until the 1990s.