Turritopsis Nutricula is anything but a quitter. This little jellyfish is the only animal we know to be immortal. It spends its infant stage as a polyp then becomes a sexually mature medusa. But unlike other jellies, after it reproduces it refuses to die and instead returns back to the polyp stage through a process called transdifferentiation. This cycle can continue indefinitely; however, the animal can still succumb to disease or being eaten. I like its scientific name too.. it makes me think of a vampire triceratops (which may be my new favorite hybrid animal).
One of my little bunnies, Squirrel, is in the animal hospital tonight and I miss her dearly. If she makes it out I must remember to teach her this transdifferentiation thingamajig.
I hope Squirrel is ok.
Also, speaking of vampire-animal hybrids: http://www.huffingtonpost.com/2010/02/16/vampire-squid-threatened_n_456871.html