Ideas for a haunted forest?

It's a dense forest. In the middle of the forest there is an haunted area for certain sq.meters with fencing and board written as "Haunted Area". There is no one to guard this area. The board is just to alert people who go by that side. Anybody can enter that area but people of that area never does it as they have experienced many horrible incidents in the past. There is only one spirit. This haunting spirit has a principle. If five men or women enter this area, it haunts the first who steps inside and attempts to kill the others. It never haunts more than one and if the haunted person quits that area the spirit too quits.