Few sports are more dangerous than boxing. Although there is a risk of potential injury in any athletic endeavor, in the sweet science, hurting is the entire point.
There's a reason boxing people like to say, "You don't play boxing."
So even at moments of high drama and excitement, the shadow of terror can lurk. In the best of circumstances, the referees, ringside physicians and fighters' seconds all play their roles to prevent tragedy and keep this brutal sport still a sport.
And in compiling this list, I have omitted actual tragedies. The moments I'm detailing here were scary, but no significant long-term harm seems to have come from them.
Last June, light middleweight contender Alfredo Angulo engaged in a war with Erislandy Lara. El Perro dropped his slick-countering opponent in Rounds 4 and 9 and was ahead on one of three cards after nine rounds.
But in the 10th, Lara landed a perfectly placed punch to Angulo's left eye socket that made the Mexican warrior instinctively turn his back in a seeming act of surrender. Angulo's eyebrow quickly took the appearance of a Cro-Magnon man's.
That kind of disfiguring of the skull is always frightening to behold. On a visceral level, it just doesn't look right. In terms of anatomy, it can indicate broken bones and a potential risk to the brain itself.
Fortunately, things turned out fine for Angulo. Subsequent medical exams revealed no broken bones. Angulo lost by TKO that night but has been cleared to return to the ring and will do so in May on pay-per-view against Saul Alvarez.
The 10-round draw between Delvin Rodriguez and Pawel Wolak in July 2011 was one of the most exciting boxing brawls of the past decade. Wolak fought much of the fight with one eye, and by the end of the bout, the entire side of his face was grotesquely swollen.
A lot of fights have been stopped for far less. But the proud Polish warrior kept bringing it round after round, without an ounce of quit. He was able to force his way inside on the longer Rodriguez and grind out his share of rounds.
But it's tough not to speculate on how much that beating took out of Wolak. Raging Bull was cleared for a highly anticipated rematch with Rodriguez in December 2011 in Madison Square Garden on the Miguel Cotto-Antonio Margarito II pay-per-view.
This time, Rodriguez earned a one-sided decision. The blue-collar hero Wolak retired after the bout.
Many fans were already concerned for Erik Morales' health heading into this April 2011 showdown with the bigger, younger Marcos Maidana.
That Morales was an all-time great was beyond dispute. But the Mexican legend had lost five of his last nine fights, was fighting well above his best weight and was years beyond his best performances.
Maidana started to close Morales' eye in the very first round. As the fight went on, the swelling became increasingly dramatic and looked horrific by the later rounds.
Yet the crafty former champion hung tough and stayed in the fight. Even while holding your breath, hoping nothing bad would happen to him, it was impossible not to be thrilled by what Morales was accomplishing.
It was boxing at its greatest and most terrible all in the same fight. In the end, Morales lost a close fight by majority decision.
This September 2006 battle of undefeated fighters included one of the most confusing rounds of the past decade. In Round 5, referee Randy Neumann stopped the action to dock two points from Edison Miranda for a blatant headbutt.
But the hard-punching Miranda had also broken Arthur Abraham's jaw on a legal punch. As Abraham was given his five minutes to recover from the foul, the ringside physician checked his busted jaw and recommended the fight be stopped.
Foul or not, a stoppage on the legal punch would have given Miranda a TKO victory and the IBF middleweight title. Abraham instead chose to battle on for the remaining seven rounds, winning a unanimous decision.
A broken jaw is one of the most dangerous injuries to fight with. The blood loss alone can be an extreme risk, and when the jaw hangs loose, it is particularly vulnerable to a follow-up blow.
Abraham not only hung on to win, he also recovered and won many more big fights, including a rematch with Miranda by TKO.
As somebody who once had a pretty good chunk of his own ear nearly ripped off, I can testify that it actually looks a lot worse than it feels. But it looks pretty terrifying.
Sebastian Lujan's left ear was already cauliflowered heading into his February 2005 clash with Antonio Margarito. Margarito banged away at the side of Lujan's head with hooks for most of the fight, busting the ear open and making the blood flow.
By the time the fight was stopped by TKO in Round 10, Lujan's ear was hanging off his head, nearly detached.
Due to getting caught with plaster hand wraps before his fight with Shane Mosley in 2009, almost every big win of Margarito's career is viewed with an asterisk at this point. Certainly, a reinforced hand wrap would be more likely to knock an ear loose.
Sergey Kovalev is the definition of a terrifying fighter. His 2011 knockout of Roman Simakov led to the death of his fellow Russian. His Round 2 KO of Ismayl Sillakh last December was pretty scary, as well.
So it was frankly alarming when Nathan Cleverly's corner sent him out for Round 4 during his WBO light heavyweight title defense against Kovalev last August. Kovalev had dropped him twice in Round 3.
Cleverly's legs were unstable and his balance shot after rising from the second trip to the canvas. After a closing barrage by Kovalev, the referee literally carried Cleverly back to his corner.
Cleverly is a tough warrior with the heart of a champion. But that's a situation where the corner has to protect its fighter. Cleverly seems to have escaped with no permanent damage from the fight, but it could easily have gone otherwise for him.
Roy Jones could probably have a few entries on a list like this one. One of the saddest things for me as a boxing fan over the past decade has been to watch the most talented fighter of my generation get put to sleep on multiple occasions.
But this was the one that truly made me wince. In May 2011, Jones traveled to Moscow to face highly rated cruiserweight Denis Lebedev. In his prime, Roy Jones Jr. probably wouldn't have even used Lebedev as a sparring partner.
But the Russian was a tough, skilled young opponent and far too much for Jones by this point in his career. The truly terrifying thing for me in this fight were the final seconds of Round 10, when Jones wavered, bent at the waist and out on his feet, clearly unable to defend himself but still in perfect position for another vicious combination.
Lebedev deserves credit as a sportsman for recognizing that Jones was done, and referee Steve Smoger, one of the best of his profession, deserves credit for quickly jumping in.
The counter left hook Nonito Donaire landed on Fernando Montiel in February 2011 is one of the iconic punches of the past decade. The future Hall of Famer instantly collapsed to the canvas with his legs twitching.
But that's not the truly scary part. What was terrifying was that Montiel somehow made it back to his feet and referee Russell Mora amazingly waved the action to continue. Clearly out on his feet, Montiel stood on unsteady legs with his hands lowered as one of boxing's most dangerous punchers descended upon him to finish him off.
I will give Mora credit for being in position to jump in quickly when Donaire landed two more unanswered punches. But those were punches that never needed to be thrown.
I appreciate the concept of giving a championship boxer the opportunity to fight his way out of trouble, but that was clearly not going to happen in this case.
As dramatic as a single-shot knockout is, those are rarely the punches that do true, lasting damage to a fighter. The time to really worry about a fighter's health is when he is absorbing blow after blow, round after round.
Shannon Briggs' unanimous-decision loss to Vitali Klitschko in October 2010 was just such a fight.
Briggs was probably a decade past his best days when this fight took place. In the 1990s, he was a marginal contender. By 2010, he was just a big, rugged dude who could take a monster punch.
That ability to take a punch was probably a detriment to him against the older Klitschko brother. Briggs is one of the few opponents to finish a fight standing against Klitschko. But he might have taken the most punishment of any of them, as well.
Sadly, it appears Briggs is geared up for another comeback. He's scheduled to return to action this weekend in Atlanta.
A month before older brother Vitali Klitschko put a 12-round pounding on Shannon Briggs in October 2010, younger sibling Wladimir put an even worse beating on Samuel Peter.
It was a rematch of their 2005 fight, which Klitschko had won by relatively close unanimous decision. This time, it was a complete massacre.
Klitschko was already finding the range of his sledgehammer right in the opening round. Round after round, the abuse piled up. Peter's corner could easily have stopped the fight after the fifth or sixth round.
But I can understand the desire to keep letting a heavyweight challenger look for his big shot, especially against a fighter like Klitschko who is known to have a shaky chin. Still, when Klitschko finished the fight in Round 10, it had absolutely gone on for 10-15 seconds too long, as Peter continued to stumble around the ring, eating shots while neither the ref nor his corner jumped in to end the abuse.
A friend of mine named Adam Levine who is a hardcore boxing fan told me afterward, "I didn't enjoy that fight. I just felt like I was watching Sam Peter get brain damage."