Parasite Eve

PARASITE EVE is best known in the US as a hit game for Sony's PlayStation, but before it was made into a game, PARASITE EVE was a best-selling novel in Japan which was made into this popular live action film. In it, a biologist named Toshiaki Nagashima has been doing extensive research on mitochondria, cellular organelles that produce energy through cellular respiration, contain vital DNA, and behave like parasites. When Toshiaki's beautiful young wife dies, he decides to replicate her using her mitochondria, and is surprised when this replicant takes on a gelatinous form that can morph into anything. Taking the form of Toshiaki's assistant, Sachiko, the mitochondria seduce Toshiaki and then tell him that they have been using humans as hosts and plan to take over the world with the new species that Toshiaki has unwittingly fathered. (official distributor synopsis)