This clip comes from Post-Shift Custom Night, a fan-made Five Nights at Freddy's style game where players survive a custom night against twisted animatronics including Nightmare Scrap Baby and Revenant Bonnie. When one of them reaches the player, the game triggers a loud FNAF jumpscare scream, and that moment was lifted onto soundboards for reuse outside the game. Horror creators keep using it because it is instantly recognisable to FNAF fans, short enough for edits and memes, and reliably startling even for viewers who know it is coming.