This video was posted by a user on Facebook seeking an explanation for a strange shape that seems to be standing outside the backdoor, and move slowly off-screen after his girlfriend throws something out the backdoor. In the latter half of the video, I've zoomed in on the active area.
This video was very intriguing, because the movement is very deliberate and precise, and does not seem to be caused by anything immediately noticeable within the scene. However, the action itself seemed very mechanical and non-organic. It almost looks like a car pulling away. Upon opening the video in VLC, and zooming in, the strange object is immediately apparent because of the bloom effect on the window. Whatever moves later in the video, is already present outside the window before the woman throws anything outside the door. My initial thought was that we saw a reflection on the window coming through from off-screen to the right.
We voiced this theory to the poster, who let us know that this wouldn't be possible because off-screen to the right was their backyard, and surrounded by a high fence. Then, Andrea noticed another prominent movement in the window on the video's upper-left side. When you zoom into this area, you see the synchronization of the action between these two motions.
You can see that the reflection is that of a chain-link fence with a white fabric of some kind draped over it. The wind seems to catch it and swing it open. This movement is what we see in the window.
Given the visual evidence, we have to conclude that, though the imagery is creepy, it is not paranormal.