Mr Krupp is Benjamin Krupp, the strict principal of Jerome Horwitz Elementary in Dav Pilkey's Captain Underpants books, first published in 1997 and later adapted into a 2017 animated film. The fire in the hole line pairs that familiar authoritarian character with a warning phrase long used before explosions, which became a widely repeated meme shout online in short edits and gaming clips. On soundboards the clip survives because it is instantly recognizable, takes barely a second, and can be dropped into almost any moment of impending disaster for comic effect.