There's a species of jellyfish that's immortal - Apparently.
The Turritopsis dohrnii, also known as the "immortal jellyfish," can transform its body into a younger state through a process called transdifferentiation. This means it can essentially revert back into its polyp stage, which is the juvenile form of a jellyfish, and then grow back into an adult again. This process can be repeated indefinitely, making the Turritopsis dohrnii theoretically immortal. This unique ability has made it a subject of scientific study, particularly in the fields of biology and aging research.