Listen, I don’t want to live forever. First of all, it’d take a really long time to work enough to save up for that long of a retirement. And I dunno, I’m a writer. I live by deadlines. And there ain’t no bigger deadline than your own inevitable death. But there’s one creature that doesn’t need to get hung up on retirement or deadlines, and accordingly it could well be immortal. This is the bizarre existence of the hydra, a half-inch tube of jelly that inhabits fresh water all over the world, where it lives a long, long time under the right conditions—and if you don’t assault it. Yet even then, it has remarkable powers of regeneration. Cut it in half and you’ll eventually end up with two hydra. Mix a bunch of them up in a test tube, break them all apart into single cells, and still they’ll re-form into a ball and split off as individuals. Yeah, I know, that doesn’t really seem possible. But stick with me here. As Kermit once said, it’s not easy being green. These transgenic hydra, which are loaded with a green florescent protein, would no doubt confirm that if they too had a puppeteer making them say stuff. Rob Steele Who Wants to Live Forever This is a supremely simple animal, belonging to the same group as jellyfish, the cnidarians. “I sometimes describe hydras sort of like a little free-living piece of intestine,” said hydrobiologist Rob Steele of the University of California, Irvine. At one end is a sticky disk, which the hydra uses to anchor itself, and at the other is a mouth and tentacles packed with stinging cells, which fire toxic harpoons into prey. Holding the quarry in place, the hydra then ratchets its mouth over the victim—typically a tiny crustacean called a water flea—until it’s entirely enveloped. More via WIRED.