The power of Tony Ayala. Due to the body shots Bobby Czyz took from Tony in sparring, he got physically sick and lost his lunch. And then there is the Cuevas incident.
Depends on the source McVey. Have read varying accounts - as you'll see if you search around. Whether Carnera was 6ft 5in or 6ft 8ins he was none-the-less an absolute monster for his time, as a 5 ft 10ins person in those days was considered tall. Just as amazing was his very basic boxing ability and lack of punching power. It was widely believed that his early fights were fixed, and it wasn't till later on when there was no fix in place that he got into strife. Still he did get to be heavyweight champ - most haven't.
nigel benn was a freak in the way that if you hurt him, god help you, the best way to fight him was to try not to hit him.