It is the night before the post.
At that time, I was reading a horror manga with a smart application. At the end of the manga, there was a word like "I am behind ..." which is common in horror, but the content of that manga was not too scary so even if I saw that word, I was not scared at all .
However
As soon as the screen of a black smartphone turned into a mirror, when I saw my face, I felt half of the face of a woman could be seen in the window behind it.
I immediately turned to the back, but there was nothing. Besides, here is the 10th floor of the apartment building. People can not peek from outside.