Movellans

A race of attractive humanoid androids from what they referred to as the 4X-Alpha-4 system. When they attempted to enter the Milky Way, they found themselves at war with the Daleks, many of which were now also wholly robotic.

The two opposing battle computers were locked in a logical stalemate for hundreds of years. The Movellans ultimately followed the Daleks back to Skaro, intending to kill Davros before the Daleks could use him to reprogram their computers.

The Movellans then realised that they could use the Doctor to reprogram their own computer and held Romana hostage. When he refused their demands, they threatened to ignite Skaro's atmosphere. Killing Movellans was difficult as they had self-repairing circuits.

However, they could be reprogrammed after they were deactivated by removing their power packs. The Doctor managed this, and defeated the Movellan force on Skaro.

Meanwhile, Davros was captured by the humans. Without their creator's help, the Daleks were defeated when the Movellans created a virus that destroyed Dalek casing on contact. After defeating their enemies, the Movellans presumably abandoned their interest in conquering the Milky Way.