As you reach room 559 in the mansion, the environment changes. The rooms now look like a forest. There's also deer roaming around, grazing. When you approach them, they reveal sharp teeth and bite at you, forcing you to run into the next room and barricade the door. As you begin to calm down and bandage your wounds, a red portal opens up in the middle of the room, and out floats a weird deer-like demonic figure, staring at you with glowing white eyes and sharp teeth. It then speaks without moving its mouth in a distorted voice...probably because it's lacking a lower jaw.

"Why do you run, child?"