The phrase comes from Karyl, a main character in Princess Connect! Re:Dive, the Japanese role-playing game and anime series centred on a guild of adventurers. Muri is the Japanese word for impossible, and repeating it three times turns a simple refusal into a memorable catchphrase that fans began clipping, sharing and remixing in short videos. Because the meaning is clear from her tone alone, the sound travels well beyond viewers who know the series, and it remains popular as a quick, humorous way to say no without a lengthy explanation.