After moving into a new house, you find a hidden door to an underground passageway. Well, not you. Your dog. Like the cats he grew up with in your previous home, he digs around after he does his business—even if it’s just air over the floor. But when you looked over to clean it up, there was nothing there. After all, he was toilet trained and he would never do that even in a new environment. But his scratching had moved a hastily placed tile, and lifting the said tile revealed the latch to a hidden door. It creaked loudly when you opened it, like it had never been touched in a long time. Puffed came the cloud of dust, and your dog angrily growled at something you cannot see.