Brak's father was never originally intended to be so short. An error was made when compositing a scene and Dad's file was made too small in comparison to everything else. Nevertheless, it was such a hilarious mistake that they left him they way he was.
In the episode "Time Machine", Zorak remembers his days in Grandma Prison, and in the flashback, he's wearing a prison uniform with the number 655321 on it. This was the prisoner number of Malcolm McDowell's Alex in the movie A Clockwork Orange.