Turritopsis nutricula may indeed be Earth's only immortal creature.

Who wants to live forever? This question has been answered by an inconspicuous water creature who potentially does live forever. The Turritopsis nutricula (Immortal Jellyfish, to us) never dies naturally. It can do this because it can alter the state of a cell, transforming it into another cell type. This phenomenon is called transdifferentiation, and is usually seen only when parts of an organ regenerate. But, it appears to occur normally in the Turritopsis' life cycle.

Jellyfish usually die after propagating but Turritopsis reverts to a sexually immature stage after reaching adulthood and is capable of rejuvenating itself. The 4-5mm diameter creature, is the only known animal that is capable of reverting to its juvenile polyp state. Theoretically, this cycle can repeat indefinitely, rendering it potentially immortal.

Normally found in tropical waters, Turritopsis is spreading across the world as ships' ballast water is dumped in ports.

As can be expected, the jellyfish and its reversal of the aging process is the focus of research by marine biologists and geneticists. The scientific and monetary possibilities are enormous with the end result being eternal life on earth.

Someday we may be asking ourselves the opposite question, "Why would you want to live forever?"

Read more:

Turritopsis Nutricula: The World's Only "Immortal" Creature | The Times

Turritopsis Nutricula (Immortal Jellyfish) | Jellyfish Facts

Cheating Death | Developmental Biology Online