The gang decides to build their own robot, but can't figure out why it just stands there when they give it orders. Slicker tells them the robot needs some ""invisible rays."" He offers to sell a box of rays to them, and while they're going off to find some money, he puts Boxcar into the robot suit. When the gang returns, they pour the invisible rays into the robot's mouth, and sure enough, he starts obeying their commands. Before long, the robot goes berserk and makes a mess of Froggy's yard.
