過呼吸ダンス (Kakokyuu Dance)

Background
The song was orignally uploaded onto Nico Nico Douga on August 3, 2011. Currently, it has recevied more than 200,000 views and has gotten into the Nico Hall of Fame. It is also one of Nashimoto-P's most known songs.

While the song has many interpetations, it could be about a girl who is hyeperventilating and dying.