Some jellyfish species, including Turritopsis dohrnii, Laodicea undulata, and Aurelia, are able to revert to the polyp stage even after reproducing (so called life cycle reversal), rather than dying as in other jellyfish. Consequently, these species are considered biologically immortal and has no maximum lifespan.
Biologically Immortal
"‘I’m bored’ is a useless thing to say. I mean, you live in a great, big, vast world that you’ve seen none percent of. Even the inside of your own mind is endless, it goes on forever, inwardly, do you understand? The fact that you’re alive is amazing, so you don’t get to say ‘I’m bored.’"
-Louis C.K. (via vacants)