The phrase is Russian slang, with ne lez meaning do not get in or do not meddle and blyat acting as a blunt profanity intensifier. Rather than coming from a widely identified film or television scene, it circulates online as a short reaction clip in Russian-speaking meme edits, where its directness does the comedy. Creators reuse it because the line needs no translation for its tone to land, and because a one-second warning fits neatly into fast-paced videos, pranks and argument scenes.