Killing Stalkingキリング・ストーキング (Japanese); 킬링 스토킹 (Korean)

Yoonbum, a scrawny quiet boy, has a crush on one of the most popular and handsome guys in school, Sangwoo. One day, with Yoonbum's obsession towards Sangwoo reaching its peak, Yoonbum decides to enter Sangwoo's home. But what he saw inside was not the Sangwoo he had dreamed of.