Mike Tyson features in four of the other top 10. Along with being one of the heaviest punching heavyweights, Tyson spent three years in prison for rape and tore part of Evander Holyfield's ear off with his teeth.
Prior to Tyson's defeat to Lennox Lewis in 2002, the sixth most watched event, a press conference brawl erupted with their respective entourages. Not the first or last time we've seen that.
Eighth spot goes to drug cheat Brock Lesnar and his return against Frank Mir for the UFC's 100th promotion.
And on it goes. Controversy sells.
As this latest McGregor-Nurmagomedov example disgracefully demonstrates, promotion is a dangerous line to tread.
The purpose here is not to play the blame game. Two wrongs never make a right.
McGregor and Nurmagomedov should be equally ashamed by their antics in fuelling and sparking such violent scenes in Las Vegas that could easily have left spectators injured.
Both, however, will benefit handsomely as a result.
Already McGregor has signposted a rematch, one that will no doubt draw widespread attention, and even bigger purses.
Sin City this ruckus was indeed; another black eye for a sport accustomed to pushing boundaries while desperately seeking to maintain a global footprint.
Whatever your view of the ugly aftermath, stoking racial and religious tensions is never a good idea.
Enough hatred, extremists and egotistical politicians exist without giving prejudice pride of place in the spotlight.
Accusations and taunts McGregor espoused in the lead up to this fight are no longer accepted in most integrated modern societies.
Yet because they came behind the fight banner, many were glossed over until Nurmagomedov lost control and any form of discipline.
Mind games play a major role in the hype before any headline fight. Look at the theatrics surrounding Tyson Fury and Deontay Wilder's world tour.
This time, though, the line between sanctioned fighting and assault was scrubbed out. This was one and the same event.
Surely, it must now register that deeply personal attacks can touch the souls of many more than those who verbal jibes are directed towards.
Violent clashes outside the Vegas arena between rival Russian and Irish supporters highlight the far-reaching negative influence this promotion had.
Intentional or not, the consequences are clear.
Nurmagomedov could have been the bigger man by taking his convincing victory with grace and class.
Instead his post-fight actions completely overshadowed what should have been his crowning moment.
Leaping over the cage to target McGregor's stablemate Dillon Danis inspired others from his team to do likewise, leading to three arrests for their cowardly attacks on a defeated McGregor, who had his back turned.
McGregor, of course, is far from dissolved of fault with footage revealing he threw a punch at Nurmagomedov's cousin, Abubakar, while atop the cage during the fracas.
Ugly, ugly, scenes.
Perhaps the best example of the UFC condoning criminal activity came with the genesis for this fight; the incident in which McGregor attacked Nurmagomedov's bus – throwing a metal handcart through the window.
Flipping script now to suggest "this isn't what we do – this isn't how we act" is as two faced as it gets.
The nature of the fight game determines it will always attract colourful characters. This much will never change. But that does not mean all decency need be abandoned.
Even the entertainment business has guiding rules or principles. Personality is not a caveat for cultural sledges and slander.
Anthony Joshua and Joseph Parker are among modern-day fighters proving it is possible to pocket millions for knocking out opponents while retaining dignity in doing so.
But it was Robert Whittaker, the New Zealand-born UFC middleweight champion, who summed it up best with this poignant quote from Canadian-born, Gaza-raised activist Mohamed Zeyara: "If they respect you, respect them. If they disrespect you, still respect them. Do not allow the actions of others to decrease your good manners, because you represent yourself, not others."
Fighting in any form is a ruthless, bloody trade but the bell should always signal time to down tools and walk away.
Nobody needs to witness this chaotic collaboration again. But this is the promotion game, so you can almost guarantee we will.
