Untan, also known as 'Un-tan,' is a fan-created personification and meme rooted in the popular anime series K-On!. It primarily focuses on the character Yui Hirasawa, capturing her idiosyncratic and 'moe' personality traits. The meme gained significant traction through a rhythmic fan-made animation where the character repeatedly says 'Un,' creating a hypnotic and cute loop. Over the years, Untan has evolved into a symbol of pure, chaotic cuteness within the anime community, used by fans to represent moments of simple-minded joy or rhythmic obsession. It remains a staple template for reaction memes that require a touch of innocent absurdity.