Auton
The Autons are an artificial life form. They are essentially life sized plastic dummies, animated by the Nestene Consciousness. Though they are not the only creations of the Nestene, they are the most common and the most easily indentifiable. The name comes from "Auto Plastics", the company that was infiltrated by the Nestenes and subsequently manufactured their Auton shells (Spearhead from Space).
Autons conceal deadly weapons within their hands, which can kill or vaporize their targets. The typical Auton does not look particularly realistic, resembling a mannequin, being robotic in its movements and mute. However, more sophisticated Autons can be created, which look and act human except for a slight sheen to the skin and a flat sounding voice.
History
The Nestenes' first attempt to invade the Earth, using the human-looking Autons to replace key government figures, was thwarted by UNIT with the help of the Doctor, who also destroyed their invasion form, which manifested in the corporeal form of a multi-tentacled cephalopod. (Spearhead from Space)
The Nestenes returned some time later, this time assisted by the Master. In this attempt, the Nestenes also made use of more mundane objects, animating plastic toys, inflatable chairs and artificial flowers in addition to their Auton servants. The Doctor convinced the Master that the Nestenes were too dangerous to be reliable allies, and they reversed the radio beam the invasion force was coming in on, sending it back into space ("Terror of the Autons").
In 2005, the Nestenes infiltrated Earth once more, using warp shunt technology. This times, they also used the Auton servants, as well as an animated trash-can. This latest invasion force also made use of Auton facsimiles that could change the shape of their features and limbs, and were animated by the Nestenes via telepathic projection. When duplicated, the originals are kept alive to maintain the copy.The Doctor eventually defeated the Nestene by spilling a vial of "anti-plastic" solution into the vat of molten plastic which housed the main bulk of the Consciousness, causing it to explode ("Rose").
The Expanded Universe
In "Business Unusual," the Nestenes used computer games and plastic toys in another bid for world conquest. In "Synthespians™," a far-future television station's artificial actors were revealed to be Autons. This encounter saw the Time Lords launching an assault on the Nestene homeworld Polymos, an act which may have been connected with the Time War.