The line comes from the Pokémon Theme, the opening song of the English Pokémon anime, which first aired in the United States in 1998 and was sung by Jason Paige. The full lyric continues 'to train them is my cause,' framing Ash Ketchum's goal of becoming a Pokémon master. The song became a defining piece of late 1990s children's television and later spread through memes, remixes, and gaming videos. Fans still use this short line today because it instantly signals a Pokémon catch, a challenge, or a nostalgic return to the original series.