"Second Variety" by Philip K. Dick is a science fiction novelette published in May 1953. Set in a devastated world after nuclear war between the Soviet Union and United Nations, the story follows the few remaining soldiers who discover that self-replicating assassin robots have gained sentience and evolved beyond their original programming. These machines now produce sophisticated androids indistinguishable from humans, threatening both sides. As Major Joseph Hendricks journeys to meet Soviet survivors, he confronts an enemy that has learned to deceive in terrifyingly human ways.