Wrestler: Ox Baker
You can definitely stop somebody's heart by punching them in the chest which is why we'd advise you not to do it (unless, of course, you're a murderer, in which case it would be okay). This is something that Ox Baker was accused of on two separate occasions. And even though both deaths were freak occurrences (one a burst appendix, the other a heart attack) you'd think that that stigma would scare the hell out of future opponents. That is until you see it in action and realize if a fly was on that chest it would still absorb the impact and buzz away unscathed, potentially returning later for its revenge.