Hakusai drew Pumpking in Pop'n style (she's well known for drawing Vocaloid characters in Pop'n style a lot, especially on NicoDouga) and okenoruk made him sing "Sumidagawa Karenka" from "Pop'n Music 18".
Thank you!

Art by 白菜/mute
http://twaud.io/rslQ
Pop'n Music 18: 隅田川夏恋歌 - Pumpking
(UST and mix by okenoruk)