A dark, humanoid shadow with indistinct, blurry edges suddenly appears at the top of a dimly lit staircase. The staircase is viewed from the side, moving diagonally from right to left. The shadow begins to slowly descend the steps with unsettling, deliberate movements. The lighting in the scene is warm and muted, casting faint reflections on the walls and steps. The shadow's motion is slightly distorted, as though shifting between dimensions, creating a sense of unease. The background is transparent, allowing seamless integration with an existing video of a stairwell With Dream Machine AI