けいオスユニおん! (Pronounced like "CHAOS UNION")

Pictures depicting crossovers with K-ON! and Hirasawa Susumu. Stems from the fact that K-ON takes names from Hirasawa's band known as P-MODEL. "Keiosuyunion" comes from Hirasawa's company known as "CHAOS UNION", and a play on words.

Common jokes include, but are not limited to: Hirasawa Susumu as Hirasawa Yui's father, P-MODEL and Hokago Tea Time crossovers, and references to Susumu Hirasawa and P-MODEL works.