What can the jellyfish Turritopsis dohrnii do that almost no other animal can?

The answer

After reaching adulthood, this species can transform back into a polyp and restart its life cycle, which is why it's nicknamed the "immortal jellyfish." Predators, disease, and injury can still kill it; aging just isn't the usual dead end.

Correct answer: Revert from adult back to a juvenile polyp stage