Mr. Psycho was a House Robot who made his debut in the sixth series and was designed by Robin Englebright. Mr. Psycho was by far the heaviest of the House Robots in the original run, weighing in at 750kg, and the largest robot ever to appear in Robot Wars history. He was based on Bill Sykes, a character from the Charles Dickens novel Oliver Twist, and his original working name during the design process was Psychsy. Mr. Psycho was also introduced with Growler, a robot which was a take on Bill Sykes' dog, Bullseye.