The 'Poop Knife' meme originated from a viral 2018 Reddit post in the r/confessions subreddit, where a user shared that their family used a dedicated kitchen knife to break up unusually large bowel movements so they would flush. The author lived their entire life assuming this was a common household practice until a social encounter at a friend's house revealed it was a unique and bizarre family habit. The story quickly ascended to legendary status in internet folklore, symbolizing the shocking realization that a private family tradition is actually a gross anomaly. It is now used to mock socially awkward situations, weird family secrets, or simply to reference one of the most famous 'cringe' stories in web history.