Hydroflax

King Hydroflax was a merciless conqueror and pillager whose subjects included the people of Mendorax Dellora and the Shoal of the Winter Harmony. He was infamous as "the Butcher of the Bone Meadows", who ate his enemies after battle, alive or dead. He consisted of a cybernetic head and a massive robot body with an autonomous computer.

In 5343, Hydroflax led a raid on the Halassi Vaults. The Vaults exploded in the ensuing firefight, driving the Halassi Androvar into his skull. River Song, who had been tasked by the Halassi to retrieve the diamond, posed as Hydroflax's nurse and seduced him into marrying her. Days later, she crashed his flying saucer into Mendorax Dellora, knowing she would intersect the Doctor's timestream there. (TV: The Husbands of River Song)