The 'FNAF Beatbox' or 'Har Har Har Har' meme stems from a viral video of an animatronic-style beatbox performance of the Five Nights at Freddy's theme song. The sound, often transcribed as 'Har Har Har Har Har' or 'Oin Oin Oin Oin,' gained massive traction on TikTok and YouTube as a shitpost and bait-and-switch format. It typically features a low-quality or 3D-rendered Freddy Fazbear nodding to the beat, often appearing unexpectedly in video edits to startle or amuse the viewer. The meme’s longevity is tied to the enduring popularity of the FNAF franchise and the hypnotic, repetitive nature of the vocalized theme music, making it a staple of modern internet 'brainrot' humor and ironic fan content.