They don't exist until they do. There was the haunted mirror of my lady who I loved, and we shared a bed, in this gothic old house.
I watched her comb her hair and move her silkily soft arms. But the demon on the other side, could not mimic the movements, of my angel but tried in vain.
It was a pathetic attempt to claim her soul, and we bailed out of there and smashed the glass into a thousand little shards.