Nightmare Mangle is a twisted version of Mangle, the mangled fox animatronic first introduced in Five Nights at Freddy's 2, brought back for Ultimate Custom Night, the 2018 crossover game that lets players face dozens of animatronics at once. In that game, its harsh, glitching audio helps signal its attack, and fans soon ripped and shared the clip on soundboards for use outside the game. It remains popular because it is instantly recognisable to Five Nights at Freddy's fans and works as a compact, startling scare in edits, streams, and reaction videos.