The clip is built around the Korean name Choi Deok Su and a single shouted 'eo', a common Korean interjection used when someone is startled or caught off guard. While its exact original video is not widely documented, the one-second shout has circulated online as a compact reaction sound, valued because it needs no translation to land. Its brevity makes it easy to drop into memes, gaming clips and short-form videos, where a loud, human reaction can sell surprise better than a caption, and that instant readability is why it keeps being reused.