When you begin to fall asleep, your body stiffens and you forget who you are. The room around you changes strangely almost imperceptibly. A space-within-space opens above you where your eyes would be if you were standing up. There are things there with many voices; that place is home, and you know these things far better than you know anything in 'real life.'
When you're dreaming, there are people, places and things that are very familiar. You may be perfectly comfortable around them, or simply pay them no mind. They are what you remember about who you are - what you'd forgotten when you were going here.
But if you look for all of this, stay aware long enough... there are blank, empty things - somehow just as alive as the familiar. They are everywhere; everything - people, places and things, like all else - but strange, empty... and above all else - hostile.
Here is the dark shape of a woman railing against your presence. You shouldn't be here. There is a tiny place in shadows under tree-roots, somehow larger than the sky, slowly sucking away the familiar inhabitants of your world, imitating until they become them. They make you dream days in minutes; they masquerade as the ones you thought were familiar, enact in strange and twisted dream-logic the familiars'... how shall I say it... deterioration.
In time (and it may seem like a long time, though only minutes pass in 'real life') you will no longer have any sense of your self. Once you've found them, and come this far, it's too late.
You were never the one observing this world - you were the creation of the familiar things. They were not simply dream characters; they were every thought and emotion that made the real world what it appeared to be. The empty things are the death of that. The thing is, it never ends. You are always slowly dying, in dreams.
This is not a made-up story. I have made some "conclusions" to be more descriptive, but I don't really know what's going on. But if you're falling asleep and feel that there are... ancient, familiar things around you... strange, hostile, somehow vaguely sad things, they are simply 'your' (for you are many) true home: the absence of things that die.