Second Variety
"Second Variety" is a science fiction novelette by American writer Philip K. Dick, first published in Space Science Fiction magazine, in May 1953, with illustrations by Alex Ebel. Set in a world where a war between the Soviet Union and the United Nations has reduced most of the world to a barren wasteland, the story concerns the discovery, by the few remaining soldiers left, that self-replicating robots originally built to assassinate Soviet agents have gained sentience and are now plotting against both sides.