Mr. K.K.
From Nookipedia, the Animal Crossing wiki
Mr. K.K. is a merry, but melancholic song at the same time. Deena, Al, Ozzie, Charlise, Hambo, and Teddy play this song in their house. Pinky, Walker, Pashmina, Beau, Teddy, Sydney, Bunnie, Maple and Bluebear are featured on the album cover.