Horrid Henry began as a series of children's books by Francesca Simon, first published in 1994, before becoming an animated television series in 2006. The show's rock-driven theme matched Henry's rebellious personality, with loud guitar at the centre of its sound. Clips and riffs from the series later spread online through fan edits, soundboards and short videos, where the guitar burst became shorthand for mischief. Its lasting appeal is nostalgia for viewers who grew up with the character and instant recognition even out of context.