Not only that, it looks like he had some kind of a seizure on the way down or while hitting the deck. He was hauled off stiff as a board. Could have suffered some very severe permanent brain damage. Every so often things like that happen to professional boxers. Just shows what can happen to somebody who’s out of shape and hasn’t done any real boxing or MMA training. A human fist, when used by somebody in good shape who knows how to do it, is a powerful weapon that can easily inflict death or great bodily harm. Wallops like this seldom happen even in professional boxing matches.
He was gone before hitting the ground.