The ruler sound comes from Baldi’s Basics in Education and Learning, a 2018 indie horror game created by Micah McGonigal, also known as mystman12. Baldi uses the ruler while chasing the player after incorrect answers, with the audible strikes helping signal his movement and increasing threat. The game’s parody of low-budget educational software became widely recognized through gameplay videos and online memes. The ruler noise remains popular because it communicates Baldi’s presence instantly, even without showing the character or surrounding classroom.