Void

The void is a simple, completely empty space when there is nothing else for your dream to display. It is usually only used to be frightening, lonely, or miserable.

Description
It's not easy to describe a literal void, but it will usually have some kind of defining feature in its center. This will be either an area of light to give a frame of reference to the floor and/or some sort of centerpiece object. This location may often be summoned as an arena for a direct confrontation with a Mare. Any sort of friendly bystander entity will most likely not be found in such a place.