So I was sitting in my chair and I called my dad up to say hi and talk, but when he answered, he couldn't hear me but in the static background I could hear whispers and as my dad kept saying "hello?" I hear a whisper say "look behind you." It was clear as day and then the phone hung up. I called my dad back and we talked and I hung up. [spoiler]2fukinsp00ky4me[/spoiler]
EDIT: I looked behind me and there was nothing there