Megosztott hang

It started on the third night... At first, I thought it was just my imagination... But the mirror felt different... Every time I looked at it, I felt like something was watching me... Then one night... I saw something move behind me... I froze... But when I turned around... There was no one there... I looked back at the mirror... And that’s when I saw it... It was smiling... But the worst part... It wasn’t me.