The audio is taken from Pluto's Kid Brother, a Disney Pluto cartoon released on April 12, 1946. In the short, Pluto is frustrated by his smaller younger brother, whose energetic barking and complaining yelps provide much of the comedy without any dialogue. Because the performance is pure cartoon animal sound, editors later lifted it as a clean, reusable puppy effect. It remains popular online for pet edits and retro animation posts, since the old Disney sound work still reads clearly even in short modern clips.