Mandrake was a programmer for the speculator computer at the Krib bank.

As a child, he piloted a High Goliax for fun to clear planets for development, and saw what the High Goliax saw translated as a childish game called the Mumbo-Game. When the speculator began singing, he queued in line to tell the bank manager Kingfish that the computer began singing "home" repeatedly. The Tenth Doctor went to have a look at the system and realised that the organic processors were slaves. The Doctor told Mandrake to attach the bank's free-reins to their "tentacles", while the Doctor changed control from the Krib's accumulator to the speculator to allow them to move freely. This put Mandrake out of a job. As the slaves, which were in fact the High Goliax minds, reattached themselves to the High Goliax's heads, Mandrake evacuated the children playing inside their heads. (COMIC: The Woman Who Sold the World)