The phrase cooked has become common online slang for being exhausted, defeated, or caught in a hopeless situation, and adding granny makes the insult sound sillier and more memorable. Short clips built around a single exaggerated line like this spread easily on soundboards and in short video edits because they need no setup or explanation. Creators reuse it as a caption in audio form, letting one line sum up a whole scene. Its appeal has less to do with a specific story and more with how instantly the slang lands with viewers who already know the expression.