The line comes from the closing cards of the Looney Tunes and Merrie Melodies theatrical shorts produced by Warner Bros. from the 1930s onward, where Porky Pig traditionally stuttered out the farewell over the series theme. Generations of viewers absorbed it as the universal signal that the cartoon was over. As classic cartoons resurfaced on television and later online, the sign-off was clipped, remixed and adopted by YouTubers and meme makers as the perfect ironic outro, and it remains one of the most recognisable closing lines in animation.