When it's an adult, the "Immortal Jellyfish," scientifically named Turritopsis dohrnii, can transform its cells back to its childhood state. This usually happens when it is physically harmed, sick, or even when it is starving. The jellyfish evolved this skill in order to survive throughout history, specifically when latching onto ships. Since it can hitchhike, its DNA has spread and the not-so-rare species is emerging all over the world.
Adapted from:
https://bestlifeonline.com/random-fun-facts/
