The 'Kitler' meme refers to cats that possess a distinctive black patch of fur under their nose, resembling the toothbrush mustache of Adolf Hitler. This internet phenomenon gained massive popularity through the website 'Cats That Look Like Hitler,' which allowed users to submit photos of their 'dictatorial' pets. While the aesthetic similarity is the primary joke, the meme is typically used in a lighthearted, absurdist way to depict house cats as overly dramatic or authoritarian figures plotting world (or kitchen) domination. It remains one of the oldest and most recognizable niche feline tropes in internet history.