Fohrok

Fohrok or Fake Bohrok were a breed of false Bohrok created by the Nynrah Ghosts for the Brotherhood of Makuta. With blue and yellow markings, they resembled a Pahrak and they served in the Brotherhood's army untill the Toa Hagah destroyed them when the Toa rebelled against the BoM. They didn't use Krana, but were either programmed or taken by Kraata. The tribe of Nynrah Ghosts who built them were executed by the Dark Hunters.

Trivia

 * "Fohrok" is just a non-canon fan-made name, but the machines themselves are canon.