It started as an ordinary fall evening. Mark called his dog inside, and the moment the door closed behind him, the night took a strange and dark turn. There, standing in the backyard, was his dog…the same dog that had just run into the house.

What followed made Mark question whether the creature sleeping at the foot of his bed was really his dog at all.

In this chilling episode, Mark recounts the night he saw his dog’s double and the strange evening that followed.