Pop Cat became a widely shared internet meme around 2020, built from images of a cat named Oatmeal with a closed mouth and a dramatically opened mouth. The meme spread through reaction images, looping videos and the Popcat clicking game, where each click triggered the familiar mouth-open visual. The sound is commonly added in edits to make that visual change feel sharper and funnier. It remains popular because the joke is simple, recognizable and easy to reuse in short-form content.