Kaleidoscope of Phantasm Prison), officially abbreviated as Gerokasu (ゲロカス, lit.

Trash), is a Japanese Psychological horror visual novel developed by 07th Expansion and published by Entergram.

The story revolves around four highschoolers—Fūka Gojō, Karin Tamaru, Mina Yuasa, and Doremi Hanabusa—who are kidnapped and forced to take part in a death game.

Steel collars are placed around their necks, with chains attached to a torture chair in each corner of the room.

A large cage dangles from the ceiling, in which a silent young boy dressed in all white is trapped.

[7] The setting guidebook, titled Official Setting Material Collection "Phantasm Object" (公式設定資料集「Phantasm Object」, Kōshiki Settei Shiryōshū "Phantasm Obujekuto"), contains character designs, commentary from the cast and staff, and the drama CD script.