Hanako of the Toilet (1996)

This fun, horror-inspired animated film is all about the ghost girl "Hanako of the Toilet", a character from school ghost stories and urban legends. One day, elementary school kid Daisuke runs into Hanako in the third-floor bathroom of the North Building. She warns him that a "switching game" is about to start involving everyone. Before long, Daisuke’s homeroom teacher, Yoshiko, is out sick, and a scary new teacher, Iwayama Iwao, shows up instead.