Shane Carwin faces the biggest test of his career this Saturday as he takes on Brock Lesnar for the undisputed heavyweight title at UFC 116.
Carwin has had a lot of tests in his career, but every time he has come out on top, putting together a perfect record of 12-0.
In honor of Carwin's undefeated record, B/R MMA thought it would be appropriate to countdown the top 10 undefeated fighters in MMA.
Lyman Good is certainly doing all he can to live up to his last name.
Since making his pro MMA debut in 2005, Good has gone undefeated, winning all 10 of his fights.
While he may not be well-known to most mainstream MMA fans, Good recently fought his way through three opponents in Bellator's first welterweight tournament.
In his championship fight, Good scored an early take down against opponent Omar De La Cruz. Good trapped him up against the cage and punched his way to a TKO victory, becoming Bellator's first ever welterweight champion.
While Ryan "Darth" Bader may be a relatively new face to fans of MMA, he has put together a record of 11-0 and gone through one very "TUF" competition.
Before starting his MMA career, Bader was a three-time PAC 10 and two-time Division-1 All-American wrestler.
Bader got his start in MMA in 2007, gaining wins at smaller MMA shows in Arizona and Mexico, but it wasn't until his appearance on The Ultimate Fighter reality show that Bader really got the attention of MMA fans.
Bader was the first selection of MMA legend Antonio "Minotauro" Nogueira, winning his first three fights on the show to make it to the finale. It was there that Bader won a TKO victory with some devastating punches over Vinny Magalhaes to earn a six-fight UFC contract.
Since then, Bader has shut down the likes of Carmelo Marrero, Eric Schaefer, and most recently, Keith Jardine with his strong wrestling and stand-up skills.
Bader can next be seen putting his undefeated record on the line at UFC 119 in Indianapolis, Ind. An opponent has yet to be named.
From Victoria, British Columbia, Canada's Sarah Kaufman is the first woman to appear on this list, having put together an impressive 11-0 record while capturing two titles during her career.
Kaufman won her first seven fights via knockout on her way to capturing the Hardcore Championship Fighting Women's Bantamweight title.
She would win three more fights before earning Strikeforce's Women's Bantamweight Championship with a unanimous decision victory over Takayo Hashi in February of this year.
Kaufman, who is widely recognized as the third best female pound-for-pound fighter in MMA, has her first title defense in July when she takes on Roxanne Modafferi (15-5) at ShoMMA: Del Rosario vs. Mahe in Everrett, Wash.
British fighter John Hathaway wasn't always a mixed martial artist.
Before getting into the world of MMA, Hathaway was an open-side flanker for local rugby team Hove RFC. Hathaway decided to make the jump to MMA in 2006, and has it ever paid off.
Since making his debut, Hathaway has won 14 consecutive fights in four years.
Hathaway made his UFC debut at UFC 93 in Dublin, Ireland, in January 2009. It was there that he beat Irishman Thomas Egan via TKO with some vicious elbows.
Since then, Hathaway has climbed the welterweight rankings with wins over Rick Story and Paul Taylor. His most recent win came in the biggest fight of his life when he defeated Diego Sanchez via unanimous decision at UFC 114 in May, 2010.
After making his UFC debut in 2009, Dunham is slowly but surely making his way up the list of the top lightweight fighters in MMA.
With a record of 11-0, Dunham has shown that he is not to be taken lightly inside the cage. Two of his wins have come via knockout, while three went to the judges' scorecards. Where Dunham has really shined is with submissions, winning six fights by making his opponents tap.
The BJJ black belt got his 11th and most recent win against UFC veteran Tyson Griffin at UFC 115 in Vancouver, BC. Prior to that, Dunham submitted Efrain Escudero with an armbar to win submission of the night honours UFC Fight Night 20.
With another win or two, Dunham could find his way in the middle of the UFC lightweight title picture.
When stepping inside the cage with Muhammad "King Mo" Lawal, a fighter has to be very aware of Lawal's punching power. As if having a perfect record of 7-0 wasn't good enough, five of those wins have come via knockout.
It was however in his last fight against Gegard Mousassi that one of Lawal's fights went to a judges' decision for only the second time. Lawal was declared the winner via unanimous decision and crowned Strikeforce's light heavyweight champion.
In addition to beating Mousassi, Lawal has taken on fierce MMA veterans such as Mark Kerr and Travis Wiuff.
Lawal is set to defend his light heavyweight title for the first time in August at Strikeforce's event in Houston, Texas. An opponent has yet to be named.
As far as women fighters go, you don't get much tougher than Megumi Fujii.
Fujii, a black belt in Jiu-Jitsu and Judo, has gone a perfect 20-0 in her MMA career. Many rank her as the No. 2 pound-for-pound female fighter behind only Cristiane "Cyborg" Santos.
Fujii is a submission master inside the cage. 16 of her 20 wins have come via submission. She's also won one via knockout and three have gone to judges' scorecards.
North American fans that haven't seen Fujii in action can get their first real look at her, as she is currently competing in Bellator's 115-pound women's division.
Gray Maynard first jumped on to the MMA scene when he appeared on season five of The Ultimate Fighter.
It was in Maynard's fight against Rob Emerson at the show's finale when he really grabbed headlines. Maynard was controlling the fight, when in the second round he slammed Emerson to the mat. Emerson tapped but the referee ruled that Maynard knocked himself out with the slam and the fight could no longer continue, declaring it a no-contest.
Maynard still disputes that he was knocked out, but ever since then he has won all of his fights to put together a 9-0-1 record.
Maynard is considered to be one of the top contenders in the UFC lightweight division. With a win over fellow top lightweight Kenny Florian at UFC 118 in Boston, Maynard could very well be next in line to challenge Frankie Edgar for his title.
That could be bad news for Edgar, as Maynard is the only fighter to have recorded a win over the lightweight champion.
If there's one thing that UFC heavyweight Cain Velasquez loves to do, it's to knock guys out.
Velasquez has a record of 8-0, with seven of those wins coming via knockout. Two of his knockouts were impressive enough to earn knockout of the night honours from the UFC.
Velasquez's list of victims reads like a who's who of the UFC heavyweight division. He has defeated Chieck Kongo, Ben Rothwell, and most recently, veteran Antonio "Minotauro" Nogeuira at UFC 110 in February, 2010.
With another win inside the octagon, many believe that Velasquez would be in line to receive a shot at the UFC heavyweight title.
Shane Carwin tops the list, with an undefeated record of 12-0 and a shot at Brock Lesnar for the undisputed UFC heavyweight title at UFC 116.
While the punching power of Carwin is well known, he has won seven of his 12 fights via knockout, perhaps something that gets overlooked is his wrestling and submission skills.
Carwin has won five of his fights via submission, and before becoming an MMA star, he was a two-time NCAA Division II Wrestling National Runner-Up and the NCAA II Wrestling Heavyweight National Champion in 1999.
Carwin also likes to work fast. None of the big heavyweight's fights have gone beyond the first round.
His most recent win came against Frank Mir at UFC 111 via TKO due to some devastating punches. The win earned Carwin the interim UFC heavyweight title.
Not only is the undisputed title on the line, it is widely believed that with Fedor Emelinaneko's recent loss, the winner of the Carwin vs. Lesnar fight would catapult to the top of the MMA world heavyweight rankings.
For up-to-the-minute MMA news, stats, and updates, be sure to follow Ken Beckett on Twitter @KenBeckett