A hive-minded, peaceful race of alien telepaths, who due to their docile nature are often farmed and enslaved by humans. Natural, or “unprocessed” Ood hold their hindbrains in their hands, whereas those that have been processed have this replaced by a translator ball.
The Doctor and Rose first encountered Ood serving on Krop Tor, where the Beast of the Pit attacked their telepathic field to turn the whole flock into killers. During the Doctor’s next meeting – at Ood Operations, a refinery on the Ood Sphere – he first heard the song of the Ood, and helped liberate the Ood’s collective consciousness. Their telepathic sensitivity enabled them to foretell the return of the Master, the creation of a Doctor-Donna and the regeneration of the Tenth Doctor.
A lone Ood, called Nephew, was trapped in House’s pocket universe. He was atomised by Idris and the Doctor’s junk TARDIS materialising. Various members of the Ood race can be spotted in the Maldovarium and on Earth, hidden in a 'trap street'.