The Movellans are one of the many races inhabiting the universe of Doctor Who. They are best known for their long-standing conflict with the Daleks. The Movellans are race of humanoid robots. They are supposed to embody physical perfection, and they operate on cold, merciless logic.
Movellans are first encountered in the episode Destiny of the Daleks, in which there is an interplanetary war between the Daleks and the Movellans. Because both the Movellans and the Daleks operate solely on logic, their war has reached a stalemate. Neither side is able to get the upper hand, because each side perfectly anticipates the move of the other. It is unsurprising, then, that they both come to the same conclusion -- the only way to win the war is to incorporate illogical behavior into their strategy. The best way to do that, they again independently decide, is to capture Davros, the evil genius who created the Daleks. Both the Daleks and the Movellans travel to Skaro, the home planet of the Daleks where Davros is intombed. They attempt to unearth him, but the Doctor and Romana interfere. In the end, Davros is imprisoned on Earth, and the Movellans and the Daleks continue their war.
Over the next century, the Movellans developed a virus that infects the Daleks. It is not clear how they managed to get this accomplished, what with both sides being wholly logical and all, but somehow it happened. In the episode Resurrection of the Daleks, the desperate Daleks spring Davros from prison in order to have him cure them of the virus. Ultimately the Doctor foils their plan, although Davros does end up escaping.
It is thought that the virus succeeded in wiping out most of the Daleks, or at least the factions of Daleks that the Movellans cared about, because the Movellans make no future appearances in any episodes.
Notable Movellans:
The Movellans appeared in the following episodes of the TV show:
Sources:
http://www.bbc.co.uk/cult/doctorwho/episode_guide/destiny_daleks.shtml
http://www.mentalis.f9.co.uk/DWID/Species/Daleks/
Endless hours in front of the television as a kid