The Jetsons (1962)

Season 2: Episode 3

An unknown package delivered to Spacely Sprockets contains a robot sentry dog named "Sentro", and Spacely decides to use it to guard his "Chocolate Microchip Cookie". However, the "Galactic Sneak"—a spy for Cogswell Cogs—has pulled a Trojan Horse–type move by hiding inside Sentro's body to infiltrate Spacely's plant. When he and Sentro steal the prototype Microchip Cookie, it is up to George Jetson—who discovers a want-ad in the news for an executive secretary for Cogswell Cogs—to become "Georgina Jetstream", infiltrate Cogswell Cogs, and get Spacely's cookie back.