Spine-chiller! Titan Junior High School

Kaidan! Kyojin Chūgakkō (怪談！巨人中学校) is the 8th episode of the 1st season and the 8th episode overall of the Attack on Titan: Junior High anime, produced by Production I.G.

Overview
Following the events of the previous episode, Hange and the other upperclassmen challenge Eren's class to a test of courage. That night they arrive at school, where Hange and Levi explain the rules: they must visit the art, music, and science rooms and write their names on the blackboard. The class splits into two groups and heads out, encountering various ghostly apparitions said to be the "Seven Wonders of Attack Junior High"; there is a rumor that anyone who sees all seven will be cursed with misfortune. Finally reaching the gym, they find that the ghosts were in fact a prank orchestrated by the upperclassmen. Erwin Smith, the club's advisor, reveals that one spirit, the woman with black hair who Christa encountered, was in fact a real ghost.