The phrase comes from Brazilian Portuguese internet slang, where memo is a clipped form of mesmo, meaning really, and krai is a softened slang exclamation. Online, the two second shout circulates as a soundboard and WhatsApp style reaction, detached from any single confirmed source. Its popularity rests on the contrast between a plain statement about the number thirteen and the intense way it is delivered. Brazilian meme pages and editors reuse it for gaming clips, football jokes and everyday disbelief, which keeps the sound recognisable even outside its original context.