Specters, haunts, wraiths.... whatever word you choose to use these visions flutter just out of clear vision. They  like to play in the peripheral corners. You know or think you know you saw something but did you really? A slight movement,turn and nothings there. A shadow where no ones been. Like the dancing specks you see when you close your eyes. If you try to focus on them they move out of clear vision. The definite knowledge that someone is close to you in the dark. Turn on the light and the room is empty. Warm breath on the back of your neck when you know no one is close to you. Some find these things creepy, some find comfort in these unknown presence. Some refuse to acknowledge anythings going on at all. If they don't admit to any of it then it isn't real. Maybe they are right.... maybe they are not. I am of the opinion that its both. Sometimes real .....sometimes our imaginations getting the better of us. 
                                               Just thinking out loud for all the world to see..........