Maigo no Mike to Yandere Goshujin

Would you like to be kept as a ''pet'' by a boy who is a little... strange? On your usual way home, your attention was called by a boy whom you never met before. He said that you are his missing pet, ''Mike''. That boy, who smiled kindly at you, swept your life under your feet and out of your grasp and drove everything into madness. [Translated from NovelGame.]