Malice In Aqualand - S1.E13

While participating in a rodeo at Aqualand, Jabberjaw sees Dr. Cybron's henchmen kidnap the Rajah, and replace him with a robot duplicate. He tells the Neptunes, and Cybron tries to silence them by sending a runaway stagecoach over a cliff. When that fails, he captures Bubbles, and sends a duplicate of her to capture the others. The group rescues Bubbles and the Rajah, and discovers that Dr. Cybron himself is a robot.