No one knows how it came to be, or even how long it's been happening, but down the mainstreet in downtown Tokyo, there is an alleyway. They say it looks like any other except for one thing, down this alley is a severed hand. It can't be removed and it's never aged, but it does not move. They say it's the body of a woman who got stuck when the building was being built, they don't know how she got there, and there is nothing on the other side, but her hand has always been there. They say if you see 1 finger twitch one after the other you will have your throat slit, if you see 2 fingers twitch you will be beaten to death, if you see 3 you will be choked, and if you see 4 you will be cursed for the rest of your life.
The final 5 fingers though, if you see them all twitch one after the other, you will see a path, If you don't follow up the path they say the hand spirits you away, if you turn back you will be ripped apart by the severed hands of all the paths victims.
However, if you follow up the path you will reach a single room, if you enter the room you will see a staircase leading to an open door, if you climb the staircase, your fate is sealed. The door down will be looked and you will be forced to tramp through every floor, to get the next.
They say if you reach the top you will be chased, and if you can't get back down to the start...
You're dead.