There was once a little girl who grew to hate the world so much that she longed to extinguish every trace that tied her to it. She committed suicide, but this was not enough for her. Every single person that was a part of her life died over the next few weeks, torn limb from limb in bizarre circumstances.
It is said that she wishes to be forgotten. Any person who learns about her must be destroyed. Those who tell others of her existence are most at risk. Late at night there will be a knock at the door. Each knock will grow in intensity until you finally open it or have to leave. Then you will meet the same fate as her family.
The kicker is that it doesn’t have to be you that opens the door. If anyone else lets her in then she will come for you, wherever you are. She only needs an implicit invitation.