I don't know the exact source for this clip, but I do know how easy it would be to fake since I work with VFX professionally.
For example this might very well be a social experiment, private or academic, to study the spread of particular information on the internet.
I have many times had the idea of faking similar material myself, and out of curiosity see what kind of life it lives on the net. But I've come to the conclusion that such experiments so easily backfires due to the naivety or believers out there. But the most obvious give-away is as mentioned the lack of proper shadow on the wall behind the creature, suggesting it to have been added in post production (unless it is a multi-dimensional alien that does not cast shadows).
It's not particularly hard to create a clip like this. For example:
- Start out with a high resolution material and degrade it in post. In that way you have greater control over syncing your CG-element with the backplate (background image).
- You can either use a camera tracking software to match-move a virtual camera to the movement of the physical camera, or you can simulate the camera movement in post so your CG-element will have perfect sync and you don't have to spend time on making a perfect camera track. And of course you can do this to a certain point where your CG-element is no longer visible and you may do a transition from virtual to physical camera movement. This is actually similar to how the classic Olivers Castle crop-circle video was created, except it was done analogue, using a static backplate and re-filming the scene using a handheld camera which created the illusion that it was shot all handheld.
- It's easier to fake things that are further away from the camera, or display little parallax. Integrating a CG-element in a shot that shifts a lot in perspective (lots of parallax) requires a complete 3d-tracking which often require extensive knowledge about the surroundings you are shooting in. This russian shot display almost no parallax at all, which makes it quite easy to match up the CG with the backplate.
But one might wonder why all these strange clips are all so incredibly low resolution and heavily compressed that you almost do not see what the scene is supposed to show. Even cheaper cellphones have full HD resolution these days.