Nestene energy units, also known as Nestene spheres, were hollow, plastic meteorites utilised by the Consciousness to travel through space and as control units for the Autons. The Tenth Doctor compared them to seeds. (PROSE: Autonomy)

Each unit was a translucent polyhedron, roughly spherical but made up of flat triangular sides; they were 8.5 inches in diameter, with a volume of 3,000 cubic centimetres and ranging in colour from pink to blue to purplish-green. They moved through space in swarm formations called "clusters" and landed on worlds through a thin funnel of superheated air about twenty miles in diameter; the first wave was composed of a spearhead of five or six units, followed by another fifty or so six months later. (TV: Spearhead from Space, PROSE: Autonomy) In another invasion, energy units fell to Earth in groups of 2 to 3 to over 200. (AUDIO: Earthfall)

The Doctor kept an energy unit in his cottage. (COMIC:A Matter of Life and Death)

Energy units contained portions of Nestene intelligence, which would be collected by Autons. If they were difficult to locate, they could increase their pulsation signals as the units were alive and part of the Consciousness. One energy unit was the "Swarm Leader," which was vital to creating a Nestene creature: once all units were collected, their contained intelligences were deposited into an environment tank to allow them to manufacture a body out of plastic which would serve as the central brain of the Autons. (TV: Spearhead from Space) If an energy unit couldn't be retrieved, it could link up with a computer since Nestene energy existed as light, using computer wires defensively while the energy travelled to join the other units. (AUDIO: Bridgehead)

Independently, an energy unit could be connected directly to an Auton to animate it, (TV: Terror of the Autons) or merely be in range of an Auton. (GAME: The Christmas Trap) Alternatively, a sphere could be linked up to a satellite where it could receive the signal. A unit could vaporise itself, releasing energy and destroying the nervous system of any creature caught in it. They could shift into a liquid form, merging with other units and collecting energy, and this form would also allow them to kill directly. (HOMEVID: Auton)

A unit could send a distress signal to a spearhead cluster to attempt realignment with the cluster to be rescued. A cluster in space could bounce their signals off of a Nestene creature and tune into the plastic-based environments of a planet. If the Nestenes' manifestation was destroyed, the units would crumple into themselves and lose their direction. (PROSE: Autonomy)

In the 1980s a Nestene sphere came to Earth to a village. The locals thought that it was a fallen star and built a plastic Christmas village around it. However, all people who came to visit the Christmas village vanished. The Eleventh Doctor heard about it. Together with Amy he came to investigate. When he found the sphere he used it to close portals, which increased its range, making areas safe when it passed through the portals and closed them. He put the sphere back into hibernation and transported it to Bakelite, an uninhabited planet. (GAME: The Christmas Trap)