Shokushu Gakuen: Shokushu ni Ochita Seitokai

Original title: 触手学園 触手に堕ちた生徒会

After the disappearance of a female student, the student council members begin searching for her, but they too begin to vanish one by one. Their desire to save their friends is mocked by a looming villain: "Such insolent girls… You'll all become breeding grounds for the Tentacle Lord!" Witness the alternate realm of the Tentacle Temple and the devouring worm that swallows three schoolgirls whole.