The phrase 'lya ty krysa' comes from everyday Russian slang, where calling someone a rat means calling them a traitor or a snitch, and the drawn out scream turned it into a reusable reaction clip. It spread through Russian speaking social feeds as a short voice meme that needs no setup, then crossed over into wider meme edits where the sound alone signals betrayal. It is often grouped with other shout based clips like the scream meme, and it remains popular because the emotion is clear even without translation or context.