One of Walt Disney's favorite parade units featured an animatronic Donald Duck who would recklessly drive down Main Street with his nephews clinging onto the car for dear life.
Kids loved the maniacal float, because it appeared that Donald Duck had jumped out of the screen and into real life. Walt Disney loved it too, because he saw how excited his littlest guests got when they saw Donald seemingly driving a real car to the tune of Quack! Quack! Quack!
While guests loved it, park operations and Disney legal did not. The float was seen as being awkward to maneuver and the corporate lawyers feared what might happen if Donald Duck drove right into a group of guests watching the parade. Donald was only brought out when Mr. Disney was in the park and was sadly retired when Walt Disney passed away in 1966.