Looking Back

In the middle of the night, I was woken up by the sound of sharpening a knife from the living room. Drowsily, I walked out of the bedroom and saw my mom, her back to me, vigorously sharpening a kitchen knife under the moonlight. "Mom, what are you doing in the middle of the night?" I asked, rubbing my eyes. Without stopping her actions, she replied in an extremely cold, low voice, "Don't look at her face. I'm holding her off for you, hurry back to your room and lock the door..." Just then, my phone in my pocket vibrated. I looked down and opened the screen, seeing a text message my mom had sent five minutes ago: 'Honey, Mom has to work late tonight and won't be home. Remember to lock the door when you sleep alone.' My whole body stiffened, and the 'mom' in front of me slowly began to turn her head backward at an unbelievable angle...