School Youkai Traveler's Guide (学校妖怪紀行 ~葉~ Gakkou Youkai Kikou: You) is a one-shot short story released on August 20, 2007. It was written by Ryukishi07 and artwork is by Izumi Rei. It can be considered the Prototype for the manga.
Marie is alone in a classroom studying when she is unexpectedly greeted by a mysterious girl. The girl abruptly asks Marie if she knows of the "Seven wonders" of the school and muses there is one more—making eight. She reveals that the eighth wonder is MesoMeso-san. As Marie struggles to recognize this surreal yet familiar visitor, the girl explains the legend of MesoMeso-san—a youkai (妖怪 demon) who resides in an old school bathroom. Those who approach the bathroom at night are rumoured to have heard the weeping (めそめそ, mesomeso) of the person who had reportedly been strangled to death there. Marie indignantly tells the girl she isn't interested in scary stories.
The girl cuts Marie off by calling her name and extends her hand, offering to lead her. As Marie is bewildered by how this stranger knows her name, various visions overwhelm her, and she asks the girl who she was. The girl introduces herself as "the Dancing Higanbana" (踊る彼岸花 Odoru Higanbana) and gently takes Marie to the school bathroom as the meso meso cries engulf them.