"Scientists have discovered a jellyfish which can live forever. Turritopsis dohrnii is now officially known as the only immortal creature. ... It turns out that once the adult form of the 4.5 mm-wide species Turritopsis dohrnii have reproduced, they don't die but transform themselves back into their juvenile polyp state."
Mitsuki's rebirth isn't a magical jellyfish thing, just a jellyfish thing.
"Scientists have discovered a jellyfish which can live forever. Turritopsis dohrnii is now officially known as the only immortal creature. ... It turns out that once the adult form of the 4.5 mm-wide species Turritopsis dohrnii have reproduced, they don't die but transform themselves back into their juvenile polyp state."
Mitsuki's rebirth isn't a magical jellyfish thing, just a jellyfish thing.