I think we can all agree that living forever is a tricky business. I mean, it sure sounds good—imagining my flesh rotting away in a coffin is never a nice night-cap thought. And think of the all the traveling I could do! And all the shoes I could collect...all the books I could read! The possibilities are, well, endless.
But then there's the pesky everyone I know and love is dying all around me thing, which isn't too dreamy. Finding people I like is hard man—I don't know if I could keep up with all that socializing and all those funerals. What a drag!
Sadly, or awesomely (depends on your level of existentialism today) there's a species of jellyfish, turritopsis nutricula, which were never given the choice; they're biologically immortal. Found in both the waters of Japan and the Mediterranean Sea, these gelatinous creatures are the only known case of an animal that is capable of reverting—completely—to a sexually immature stage after having reached sexual maturity.
More amazing still, this death bypass is brought about in reaction to "adverse conditions" (like cold or predators but also just sickness and age!) which enables the jellyfish to turn back into a polyp, which is basically one evolutionary step above a larvae.
This freaky little jellyfish's ability to rebirth itself again and again has—not surprisingly—inspired scientists to see if there's a way to grow stem cells with this process; the dream is that we could hijack these jellyfish's death-cheating tactics and renew damaged or dead tissue in humans.
(Or revert old people back into babies again and again?! Now that is some juicy science fiction fodder.)
Image: Wikimedia Commons