The line comes from Courage the Cowardly Dog, the Cartoon Network animated series created by John R. Dilworth that ran from 1999 to 2002. Set in Nowhere, Kansas, the show follows Courage with Muriel and Eustace Bagge as strange, spooky threats arrive at their farmhouse. Fans share short dialogue clips from the series online because the exaggerated reactions work outside their original scenes. This box line survives as a reaction for curiosity gone wrong, especially in edits where opening something small leads to a much bigger problem.