Theoretically, this process can go on indefinitely, effectively rendering the jellyfish biologically immortal,[3][6] although in practice individuals can still die. In nature, most Turritopsis dohrnii are likely to succumb to predation or disease in the medusa stage without reverting to the polyp form.[7] --WP
if there's any word, prefix, or suffix added to 'immortal', i dont want it. 'biologically immortal', 'functionally immortal', 'spiritually immortal'. if you have to put an extra qualifier in there, meaning it's immortal-ish, then that ain't immortality
Yeah, that works for fiction. In the real world though, nothing can survive entering a black hole for example. So your definition of immortal is pretty useless outside of fiction.