Corpse Party (2015)

As graduation approaches, Naomi Nakashima and her childhood friend Satoshi Mochida join their classmates in tidying up after their final cultural festival. In a twist, class representative Ayumi Shinozaki suggests they perform a ritual called Sachiko Ever After to ensure their friendship lasts. Instead of a sentimental bond, the group finds themselves trapped in the haunted remnants of Heavenly Host Elementary School, a site marred by horrific murders. Now, they must confront the malevolent forces within and uncover their fate at this cursed institution.