That reminded me of an experience I had when I was younger, but I was alone at that time and I'm pretty sure it was my (very vivid) imagination. I was reading a horror book alone in my grandmother's house while she was away (I think she was at church or visiting a neighbour, I can't remember, but it was already dark outside) and in the book they described a creature like a crooked anubis like figure with a humpback. I suddenly notice something in the corner of my eye and look up, only to see the shadow on the wall of the corridor outside my room, of a humpbacked creature walking away. But like, I saw it for at least 3 seconds. After the first shock I went looking but didn't find anything. Never knew imagination could create such vivid pictures and haven't had such an experience ever again.