YOUR POV
I lifted my head and saw that the door to Sans room was open, but no one was there. "Hello?" I whispered softly. I saw a shadow flit out of the doorway and I leapt to my feet, snatching the stick that was laying by the bed. "Sans?....Papyrus?" I called out. I heard them both start to head upstairs, Sans lazy tread and Papyrus's bounding steps. "W-who's there" I yelped as the shadow landed in front of me. It looked up revealing its horrifying face.
I screamed and dropped the stick as he wrapped black tendrils around me enclosing my entire body. I struggled and heard Sans and Papyrus rush into the room. Sans yelled "Gaster NO!" before I felt my stomach drop and a flash of multicolored light blinded me. Then the tendrils released me and I fell to a cold, cement floor. I glanced around confused, we were in a room that had no doors or windows only drab gray cement. There was a moldy, bug-ridden mattress in the corner but nothing else. I realized that the thing- Gaster, Sans called it, had disappeared. I was alone in this strange room.