Atraxi

The Atraxi were a group forming a galactic police force.

Appearance
The Atraxi resembled giant eyeballs, set within a large crystalline structure much like a snowflake. They were able to travel in both space and an atmosphere. (DW: The Eleventh Hour)

Abilities

 * How many of these traits are technological and how many are natural is unknown.

The Atraxi were able to remotely activate and control the media on Earth, allowing them to send a message in every Human language, through every available device. They were also able to track the media, pinpointing a world-wide computer virus to its origin or learn of the planet's history. Though capable of scanning the planet on a worldwide scale, they were unable to find multi-forms when shapeshifted. The Atraxi also had a weapon capable of destroying the Earth (requiring only 20 minutes to charge) and a force field to seal the Earth for its destruction. The Atraxi who came directly to Earth was also capable of projecting holograms. (DW: The Eleventh Hour)

History
In 102 A.D., the Atraxi were among the races who joined the Alliance. They came to Stonehenge and helped imprison the Doctor in the Pandorica in order to save the Universe. (DW: The Pandorica Opens)

The Atraxi ran an extradimensional prison which contained Prisoner Zero. When Prisoner Zero escaped through a crack in space, they tried to find it, but were unable to do so. 12 years later, they were able to pinpoint it to Earth. They threatened to incinerate the Earth unless Prisoner Zero gave itself up.

Though the Doctor tried to attract their attention by activating alien technology, his sonic screwdriver burnt out before they noticed. Eventually, he created a computer virus/message and got Jeff Angelo and team of geniuses to send the message worldwide. With the message being "0", they took notice and were able to track the virus to a mobile phone, which was held by the Doctor. When the Doctor and Amy Pond trapped Prisoner Zero back in its own form, the Atraxi were able to find and contain it. Though the Atraxi attempted to leave at this point, the Doctor called them back for breaking Article 57 of the Shadow Proclamation, threatening them to leave Earth alone. (DW: The Eleventh Hour)


 * Due to the Cracks in time being negated by the Doctor, it is likely that Prisoner Zero never escaped from his prison, thus the Atraxi didn't have to come to Earth. (DW: The Big Bang)



Behind the scenes

 * It is thought that an Atraxi eye was watching River Song on a computer screen in Flesh and Stone.
 * The Eighth Doctor mentioned the planet Atraxi 3 once, it is possible this is the homeworld of the Atraxi. (EDA: Vampire Science)
 * In the original script for The Eleventh Hour, the Doctor referred to the Atraxi as a "level 20 civilisation".