I leave my house to walk my dog. When I get to the end of my driveway I look up the street and walking down this stretch of street without any street lamps is this large black quadruped shadow. At first I thought it was a dog but then I realized that whatever it was it was only shaped like a dog. I couldn't stop watching it as it came closer and it brought with it a growing sense of dread but as it reached the circle of light from the streetlamp in front of my house it vanished (like when fog dissipates, it just faded away). I continued walking my dog but the entire time I had this feeling something was following behind me. As I reached the park I was struck by the feeling that it wasn't a good idea to continue and had to turn around and go home but the entire time I had the feeling there was something back the way I had come waiting. It's been a few hours since then and I just went outside and I swear I can see it hanging out on the roof of the house across the street.
I was wondering if anybody has any insight into what this might be and if I should be worried about it.