Dalek
Later versions of the prop had more efficient wheels (from shopping carts, according to a Blue Peter episode) and were simply moved by the seated operators' feet, but they remained so heavy that when going up ramps they often had to be pushed by stagehands out of where the camera could not see. The difficulty of operating all the prop's parts at once contributed to the occasionally jerky movements of the Dalek. The latest model of the costume still has a human operator within, but the movement of the dome and eyestalk are now remotely controlled so that the operator can concentrate on the smooth movement of the Dalek and its arms.