The line comes from the B1 battle droids introduced in Star Wars: Episode I – The Phantom Menace in 1999. Built as cheap, mass produced soldiers for the Trade Federation, the droids acknowledge every order with the same cheerful roger roger, which became their signature catchphrase. It returned throughout the prequel films and The Clone Wars series, and clips later spread on YouTube and meme pages. Its mix of military formality and goofy delivery keeps it popular as a reaction sound.