Hallway Ghost

In the summer of 2002, I was in the bathroom with the dog, brushing my teeth when I saw something run past the door. This black shadow looked like a person dressed in black with a black mask on. It ran past the door, but it was hard to tell because it went by so fast. At first, I thought it was my mom going by playing a joke on me, but when I went upstairs, she was sleeping. Not to mention, I would have heard her go upstairs because the bathroom is right under the stairs. Of course, she didn’t believe me, but the thing that makes me believe it was a ghost is that the hair on my dog’s back bristled as if he had sensed something a couple of seconds before this all happened.