Ok, another part of my theory here.Mist and Fog, one common element in most Paranormal activity, this can be explained by my theory as well.Mists and fogs reveal parts of the paths that pass through it. The mist and fog reveals many things from the threads, it could be past memories, the thoughts and ideas of people and Parts of the future. Sometimes it can take it one step further, by taking on the form of which it shows, from anything like small orbs to massive creatures all the way back to people (Because it is mist the forms are 'Ghosts').
we have mist and fog, how scary is that?
It used to be very scary in England back in the late1880's when Jack the Ripper was doing his thing.