When users downloaded the file, it contained 14 seconds of white noise followed by a distorted voice saying, "Don't forget the prep school." The fandom assumed this was a leak. It wasn't. It was a fan-made hoax. But the damage was done. The term began trending, spawning thousands of pieces of fan art.
This technical phrase refers to a specific, internal developer comment and variable setup found within the game's code, specifically tied to the behavior, animations, and testing phases of the character Berdly. The Origin of "Quack Prep" quack prep deltarune