Self-replicating robot

Self Replicating robots were scavenging robots who could build more of their number. The Doctor described them as a plague. Professor Strut gave a package to the Doctor telling him it was a prsent for his brother the Lorduke of Zazz. The package contained a single Self-Replicating robot that began to create more until they had swarmed the area. One stole the Doctor's watch chain. The robot was a decendant of the Servatron of Monektoni Shug, whose spacecraft had crashed on the Moon of Zazz. Strut had found it in a rock sample he had. The Servotron on the moon began repairing the ship and creating more robots. After twenty generations on this moon they had built their own city. They were forced to periodically scramble when a warning alarm rang for a meteor shower, they hid underground. Later a meteor storm came and one large meteor hit and destroyed the city killing the robots. The Doctor used a sound similar to the meteor recall alarm to lure the robots on Zazz in Strut's rocket. They then took off for the moon. (DWM: The Gift)