Jevil is the secret jester boss from Chapter 1 of Deltarune, the 2018 role-playing game by Toby Fox, and chaos is his defining theme, from his dialogue and attacks to his unpredictable behaviour in battle. Players encounter him in the Card Kingdom after finding a hidden key, and his manic personality quickly made him a favourite for clips, edits, and memes. The short sound spread through gaming videos and Deltarune fan content, where it is now used as a quick shorthand for chaos, trickery, and sudden madness.