Matoran Sphere

Matoran Spheres were round containers created by Makuta Teridax to store Matoran in. A Matoran who was captive inside of one would lose all their memories, and their body size and shape would change prior to being placed into the pod. Teridax planned to use this memory-erasing function to reawaken the Matoran as their savior.

When Teridax impersonated Turaga Dume, he placed the real Dume inside a pod. He was eventually discovered by the Toa Metru.

There were approximately 1000 pods built. In order to awaken the Matoran trapped inside, the Toa Metru sacrificed their Toa Power, turning the former Toa into Turaga. It is unknown what the Turaga did with the Spheres then.

Ahkmou's pod was left behind in Metru Nui, lost by the Toa Metru. He was then awakened by Teridax, his memory erased, and Teridax convinced him into becoming his servant.

Known Beings Imprisoned

 * Turaga Dume
 * The Matoran of Metru Nui

Trivia

 * Two Toa Metru set canister lids could be combined to make a Matoran Sphere.