are identified: I-V, a wounded soldier, and III-V, David. II-V—the "second variety"—remains unknown. The different models are produced independently of each other in different factories. The Soviets also reveal that the U.N. protective tabs are ineffective against the new robots. Hendricks attempts to transmit a warning to his headquarters bunker, but is unable to do so. During the night, Klaus claims Rudi is the II-V and kills him, only for human organs to be revealed. The next morning, Hendricks and the two remaining Soviets return to the U.N. lines. When they reach the bunker, they discover it overrun: a crowd of David and Wounded Soldier robots attack, but Tasso destroys them with a very powerful hand grenade, stating that it was designed to destroy the robots. Hendricks and Tasso flee, leaving Klaus to the old-style claws. However, Klaus survives both the claws and the bomb blast only to be shot by Tasso, sending "gears and wheels" flying. Tasso tells Hendricks that Klaus must have been the II-V robot. Hendricks, now suffering from a wounded arm and internal injuries, hopes to escape to the Moon Base. He and Tasso search for a hidden escape rocket, which is found to be a single-seat spacecraft. Hendricks attempts to leave, but Tasso convinces him to let her leave and send back help. In his injured state, he has no choice but to agree. Hendricks provides Tasso with the signal code needed to find the Moon Base. Alone and armed with Tasso's pistol, Hendricks returns to Klaus' remains and discovers from the parts that the robot was not a II-V, but a IV-V. A group of robots then attack Hendricks, including Davids, Wounded Soldiers, and several Tasso models—the true II-V. Hendricks recognizes that he has doomed the Moon Base by sending a robot to them, and that he cannot withstand the onslaught of robots attacking him. Noticing the bombs carried by all the Tasso models, Hendricks' final thought is that the robots are already producing weapons designed for killing each other. Reception Strange Horizons called the story one of "Dick's most compelling works", and stated that it is "often singled out as one of the early stories that most anticipates Dick's preoccupations in his more famous novels". In 2004, the story was a finalist for the 1954 Retro-Hugo Award for Best Novelette. Publication history "Second Variety" was first published in the May 1953 issue of