Ood Brain

The Ood Brain was a huge living brain that was the connection between the Ood. It was found by Human's somewhere on the Ood-Sphere and then contained in warehouse 15 surrounded by a telepathic barrier so it couldn't communicate with the Ood allowing them to become slaves. Dr. Ryder managed to infiltrate Ood Operations and let the Brain communicate temporarily with the Ood which turned them against Ood Operations. It is shown to be living as Klineman Halpern threw Ryder on to it and it swallowed him. After Halpern became an Ood (thanks to Sigma) the Doctor shut off the barrier freeing the Ood from slavery.