Turritopsis nutricula is a small hydrozoan that once reaching adulthood, can transfer its cells back to childhood. This adaptive trait likely evolved in order to extend the life of the individual.

Turritopsis nutricula, or sometimes – Turritopsis dohrnii, is able to transform its cells from mature state back to immaturity, in other words – back to youth. The medusa leads a regular cycle of life, but after maturing and mating, it reverts back to its initial state – a polyp colony.