The sound comes from SpongeBob SquarePants, in the 2002 episode Mermaid Man and Barnacle Boy IV, where Patrick Star explains wumbo as the opposite of mini after SpongeBob shrinks Bikini Bottom. Patrick lists forms like I wumbo and you wumbo with complete certainty, and the scene became one of his most quoted lines. Clips and screenshots spread through early meme forums and YouTube edits, and wumbo entered fan slang for anything oversized or reversed. It remains popular because the joke is instantly understood even without the episode context.