Manga- Ibitsu

Creepiest story and manga that I've ever read! Lots of scary moments! Don't read this before going to sleep XD

14 chapters - Read here

At the middle of the night Itou Kazuki went to throw out the garbage. Unfortunately he sees a weird and frightening girl dressed in lolita dress sitting in the dumpsite. When he passed her she asked him if he has a little sister. He answered the question and quickly come back to his house. He then saw that the Lolita girl has disappeared.
{A bit of a spoiler) - There is an urban Legent about a lolita girl who is asking a question "Do you have a younger sister" and if you answered she will become your little sister no matter what!