The meme of Mugi (A character on the anime K-On with thick eybrows) became a meme after a popular hentai of her spread on /h/ and /a/ called "Black Time" and "Black Time 2" were she has sex with "foreign" black men and turns into a total slutty bitch and starts to get tattoos on her body (Most notably her ass and legs) and also did some scat fetish in the hentai.