When George Costanza's fellow marine biologists aren't removing Titleist golf balls from whale's blowholes, they've been preoccupied with discovering a species of hydrozoan or jellyfish-like aquatic organism they're dubbing "The Immortals"
Not to be confused with a 1950's doo-wop group or CGI-generated Xerxes horde battling the 300 Spartans, these "Immortals" are so named because they can live forever by virtue of the fact that they can reinvent themselves in younger and younger form only to die if they are eaten. Not unlike Joan Rivers.
This regeneration and ability to revert to its juvenile form occurs only after each completion of successful mating. Not unlike Hugh Hefner.
Scientists and doctors seeking anti-aging protocols, quite understandably, recognize The Immortals as a key to further their research into either slowing the aging process or preventing some of its more debilitating effects.
In those scientific circles, The Immortals are known as Turritopsis nutricula. I prefer "Benjamin Button-Fish".