The thing that I cannot really make out on the video is the 'secondary' movement when the animal goes down. The reason why it looks funny is that we cull plenty of animals with head shots for meat processing purposes and when an animal goes down after a good head shot the head does not move ever again. There will be absolutely no movement of the head after a brain shot and the body will drop directly to the ground (Not pretending to be a neurological expert, just what we noticed over the past few years). Sometimes up to 600 animals can be culled in about 4 days (just to give you an idea of the sampling size) and when a bullet hits the brain the head stays on the ground.
I believe the animal's rear could have slipped over a little overhang and pulled the rest of the body backwards but the head not staying on the ground is a little odd. The other scenario could be that the animal fell oddly and somehow thrown it's head upwards but that is just guessing.
Just a final though: What is faster than a regular Elk?
