Orthrus

Orthrus was a duplicate of K9 created by Inspector Drake.

Biography
Drake created Orthrus in order to frame K9 so that he could dismantle him. It took "fifteen thousand man hours" to make him. He appeared when June Turner was making a statement to protesters about Department microchips. When they started throwing fruit, Drake angrily ordered the CCPCs to arrest them. Orthrus appeared and opened fire on the Department's banners and balloons and then shot Drake. Drake issued a warrant for K9's arrest. When K9 said he had no memory of the attack, Professor Gryffen put a device on K9's tail to see if he went "walkabout" the next night.

That night, Orthrus went into the mansion and severely damaged Mariah. Darius Pike was furious with K9. Later, Drake sent two CCPCs to arrest K9. Despite what he thought K9 had done, Darius attacked a CCPC and ran with K9, Starkey and Jorjie. When they split up, Darius was alone with K9 (actually Orthrus). He noticed him acting oddly and ran when he opened fire on him. He told Starkey and Jorjie what had happened, but they didn't believe him. When Orthrus arrived, it armed its cannon at Jorjie. Starkey stepped in her way to protect her. When Orthrus prepared to fire, he was fired at by the real K9. Orthrus tried to attack K9, but was disabled. When Drake tried to arrest K9, June Turner told Drake that Project Orthrus was not approved by Department and his plot was foiled. (TV: Jaws of Orthrus)

Technology
Orthrus had all the basic capabilities of K9, such as a photon beam and flight. However since Orthrus was created using Department technology from 2050 and K9 was created in the 51st century with possible Time Lord modifications, it was inferior to the original.

Behind the scenes

 * Despite the fact K9 is voiced by John Leeson, Orthrus never spoke. It may not have been capable of speech.
 * In Greek mythology, was a two-headed dog, brother to Cerberus.