Sonic.exe began as a creepypasta horror story reimagining Sonic the Hedgehog as a demonic, murderous version of the character, and it spread through fan-made games, animations and YouTube videos that leaned into the contrast between the cheerful mascot and the horror premise. The laugh became a shorthand for that twisted version, instantly signalling that the familiar character is no longer friendly. It remains popular because horror creators and meme editors can use a single recognisable sound to flip a scene from nostalgic to unsettling.