After School Nightmare (Japanese: 放課後保健室, Hepburn: Hōkago Hokenshitsu, lit. "After School Infirmary") is a Japanese shōjo manga series written and illustrated by Setona Mizushiro. It was serialized from 2004 to 2007 in the manga magazine Princess and collected in ten tankōbon volumes. It was licensed in North America by Go! Comi, with all volumes adapted by Mallory Reaves and edited by Brynne Chandler. The story is about Mashiro Ichijo, an intersex high-school student who is forced by a teacher to work out their gender identity in a collective dream, and Mashiro's romantic relationships with two classmates, one female and one male.