For those who don’t know: Jellyfish are often described as potentially immortal because certain species, like Turritopsis dohrnii, have a unique biological ability to revert their cells to an earlier stage of life. This process, called transdifferentiation, allows the adult jellyfish to transform its mature cells back into a polyp state, essentially restarting its life cycle instead of dying. By repeatedly cycling between these stages, these jellyfish can theoretically avoid the natural aging process that most organisms face. While they can still die from disease, predation, or environmental factors, their capacity to continuously rejuvenate makes them a fascinating example of biological longevity in the natural world.