One day, I heard a scratching noise coming from the closet. It seemed that a mouse had fallen in somehow, and was trapped inside the walls. After a few days, the desperate scratching that made me so nervous had stopped. Time passed and I forgot all about the scratching, but then I began to smell something putrid. The mouse must have died, trapped inside the walls. The stench grew thicker and thicker for a week or two before suddenly dissipating. All the noise and stink that had invaded my personal space had subsided, finally. I found it interesting that I did not perceive its absence initially. When I realized the smell was gone, it somehow made me feel a little strange that there was no substantial evidence left, even though the intruder had been invisible and intangible from the beginning. In spite of that, I could sense that the spark of life had been extinguished after all the sounds of struggling, and death left its trace in the form of an unmistakable stench. The fact that even this fragment of evidence was gone soon after made me feel something deeper than simple acknowledgement of the absence of what was once present. Did any of this really happen?

 Everything happened behind the wall. It was an unknown space outside the boundary of my everyday life. In a way, it was a fictional territory; the wall was a border separating reality from illusion. All I could do was make assumptions about the unseen happenings beyond that border. I guessed it was the presence of a mouse by the sharp scratching noise, and I presumed its death when I encountered the rotten smell. The evidence that drew me into this event has vanished entirely by now. The absence of those sensory clues turned that space into a confusing realm of the unknown. I started to question my confidence in the memories of that experience. I felt trapped in my own uncertainty.