Metamorphosis: A Natural and Human History Oren Harman Basic Books (2025) “Metamorphosis is wild,” marvels historian Oren Harman. A caterpillar completely dissolves inside its chrysalis, before reconstructing itself in the shape of a butterfly. The ‘immortal jellyfish’ (Turritopsis dohrnii) reverts from its mature, floating form into a polyp that dwells on the ocean bed when threatened, only to eventually turn back into a mature jellyfish again — never dying of old age.