The Corpse Fog

Though it is called THE Corpse Fog, this supernatural phenomenon can occur many times in different places. When the souls of many many dead people converge together, one of the forms this ghostly union can take is a yellowish white, solid fog that flows like water. On rainy or foggy days, it will spread out from where it was formed, creeping along the ground like a flowing river. If something living touches it, they will come down with illnesses painful and great, and if a spirit touches it, the ghosts that make up The Corpse Fog shall try and pul the spirit into it. If you see a Corpse Fog, get to high ground, for it mimics water and water does not climb.