Actually that's what I was thinking. There is a neurological disorder in humans wherby they feel that a certain limb doesn't belong to them and they feel this really deep rooted desire to have that limb amputated. I can't remember off-hand what it's called, but it can be really disturbing to hear that some people go to self-harm, or sometimes even fail to notice that the limb is attached to them. Perhaps that can be found in pets as well? I don't think this is particularly amusing - despite the people obviously snickering away in the background of the video - this dog has real issues that need to be dealt with before he does do himself a damage. He does have a food aggression problem, I think, maybe it only shows when he has a favourite food like a bone (I had a dog exactly the same with bones, but no other food at all) but the fact that his hind left leg moves in an almost independent fashion does suggest a neurological disorder.