Nicovideo: http://www.nicovideo.jp/watch/sm23324071 English sub available.
原作:少女が見たモノ(茶々畑)
Pixiv:http://www.pixiv.net/member_illust.php?mode=medium&illust_id=40920354
Original work: The Thing Which The Girl Saw (Chachabatake)
You can read it at: http://danbooru.donmai.us/pools/7932 for translation and references explanation.