The phrase comes from the Brazilian Portuguese dub of League of Legends, where Kennen, the small yordle ninja champion, uses os olhos nunca mentem as a character line. Brazilian players clipped the short delivery from gameplay and champion selections and began reusing it outside matches as a reaction sound. Its appeal is the contrast between the serious tone and everyday situations where someone pretends to be innocent. It remains popular in short edits and soundboards because the meaning is clear even for viewers who do not play the game regularly each day.