Biosphere

After a global apocalypse that has killed almost all humans, the only survivors are childhood friends Billy (Duplass), the former president of the United States of America, and Ray (Brown), a scientist and Billy's former adviser. Billy feels responsible for causing the apocalypse, and the two live in a dome built by Ray that protects them from the outside environment. They maintain a fishpond, but become distressed when the last remaining female fish dies, leaving behind only two male fish, one of which appears to be dying. Ray stays up late one night, and discovers the possibility that the fish are undergoing sequential hermaphroditism to continue breeding, and notices a bright green light outside the dome. The next morning, Ray tells Billy about his discovery, and Billy realizes that he is also undergoing sequential hermaphroditism and is gradually developing female sex organs.