First off this will make more sense if you watch Abandoned on a Moonlit Night (Okizari Tsukiyosyou), and that video might make more sense if you watch Moonlit Bear (but it isn’t required reading).
Left Behind on a Moonlit Night (Happy Version) by 生殺しP, original song (and the song that is playing) by mothy/Akuno-P. Sung by Rin and Len Kagamine. English Hardsubs by Kanannon. Nico: sm5676350.
JSYK it is hilarious.
If you liked that, I highly recommend the Happy Version of Daughter of Evil (and Kanannon has subbed versions of the ~Happy Version~ sequels, Servant of Evil and Regret Message as well! :D)