They may have reached the top of their sport, but, for one reason or another, these guys are resigned to the record books.
Carla Esparza - UFC Women's Strawweight Champion
With how dominant Joanna Jedrzejczyk's run with the UFC Strawweight Championship was, it can be easy to forget that she wasn't actually the inaugural champion of the division.
That honour goes to Carla Cookie Monster Esparza, who claimed the title by choking out Rose Namajunas in the finale of The Ultimate Fighter 20.
Esparaza's reign was short-lived though, as her shortcomings as a striker were thoroughly exposed at the hands of Jedrzejczyk just 93 days later at UFC 185.
However, unlike another female fighter featured on this list, Esparza recovered from losing her belt to become a solid contender in the UFC. So, while her title reign may not have been the most memorable, Esparza has established a reputation as one of the toughest fighters at 115lbs.
Carlos Newton - UFC Welterweight Champion
Before Georges St-Pierre emerged as one of the most dominant forces in the history of combat sports, Anguillian-born Ontarian Carlos Newton flew the flag for Canada in the UFC.
Newton made his UFC debut in 1998, taking part in a one-night Middleweight Tournament, and reaching the final before losing a narrow decision to the legendary Dan Henderson.
Undeterred by the defeat, Newton would become an early star of the Japanese PRIDE promotion, before returning stateside in 2001 to take on the long-reigning inaugural UFC Welterweight Champion Pat Miletich. Newton shocked the MMA world by forcing the champion to submit to a bulldog choke in the second round, simultaneously producing one of the craziest visuals in the history of the young sport.
Unfortunately, the Canadian's time at the top of the sport was to be short-lived. In his first title defence, Newton took on Miletich's protege Matt Hughes and was defeated in highly unusual standards.
With Hughes locked in a deep triangle choke, the American lifted Newton into the air seemingly looking to slam his way out. Then, just as it appeared that Hughes was losing consciousness, he slammed Newton, knocking him out instantly and beginning a title reign that would go down in history.
They do say anything can happen in MMA…
Sean Sherk - UFC Lightweight Champion
Though the 155lbs weight class is now arguably the most talent-rich in the history of the sport, the UFC hasn't always seemed to have faith in the lightweight division.
After inaugural champion Jens Pulver left the UFC due to a contract dispute in 2002, the entire division was put on hiatus for more than three years.
When the promotion pulled the trigger on bringing the belt back, Sean Sherk defeated perennial contender Kenny Florian to become just the second UFC Lightweight Champion.
However, Sherk's reign at the top of the sport would prove to be short-lived. In his first title defence, the American defeated Hermes Franca in a bout where both men subsequently tested positive for banned substances.
Sherk was stripped of the belt in the aftermath of the controversy and would be knocked out by BJ Penn with the title on the line on his return.
Nicco Montano - UFC Women's Flyweight Champion
With the UFC clearly having learned nothing from Carla Esparza's brief reign as UFC Strawweight Champion, the promotion opted once again to attempt to successfully build a new weight class on the back of a season of The Ultimate Fighter.
An enduring underdog, Montano repeatedly defied expectations to earn her place in the tournament finale and went on to defeat the veteran Roxanne Modafferi to become the first-ever UFC Women's Flyweight Champion.
Unfortunately for Montano, it was mainly downhill from that point on. A botched weight-cut in what was set to be the first defence of her title against Valentina Shevchenko forced Montano out of the fight, and she was later stripped of the title by UFC President Dana White.
A litany of injuries and fight cancellations have followed and with Shevchenko's dominance at 125lbs showing no signs of slowing down, it will be interesting to see if Montano can ever fulfil her potential inside the Octagon and reclaim the belt.
Dave Menne - UFC Middleweight Champion
Of all the names in the history of this young sport that seemingly do not get enough recognition, former UFC Middleweight Champion Dave Menne has to be somewhere at the top of the list.
Menne built an impressive record during the so-called "dark ages" of mixed martial arts, travelling the world taking part in no holds barred one-night tournaments and picking up impressive wins over the likes of Carlos Newton, Chris Lytle, and Dennis Hallman.
So, when the UFC finally came calling in 2001 with a shot at the inaugural Middleweight Championship on the line Menne was quick to accept. A unanimous decision win over Gil Castillo was enough to get his name in the history books, but The Warrior's title reign would prove to be short-lived.
In his first title defence, Menne faced Brazilian Jiu-jitsu black belt Murilo Bustamante and was knocked out after just forty-four seconds of the second round.
