Kimbo Slice

On February 16, 2008, Slice fought Tank Abbott in the main event at EliteXC: Street Certified. He won by KO 43 seconds into the first round due to strikes. At the fight, his weight was announced at an all-time low of 234 lb (106 kg), a far cry from his street fighting days of 280 lb (130 kg).

On May 31, 2008, Slice fought in the main event of the first ever mixed martial arts event shown on prime time network television, EliteXC: Primetime. Though one of the judges had each fighter winning one of the first two rounds, Slice's opponent James Thompson won both on total points[19][20][21] by repeatedly taking down Slice and grounding and pounding. In the opening seconds of the third round, however, Slice threw a haymaker to Thompson's left ear, which ruptured Thompson's cauliflower. This was soon followed by three unanswered punches to a standing Thompson, which led to a referee stoppage and the controversial win for Slice. Fellow EliteXC competitor Brett Rogers was particularly critical of Slice's victory, calling Slice's performance "garbage" in a post fight interview.[22] Frank Mir was also a critic of Slice, stating in an interview that "every time Kimbo Slice fights, it sets (mixed martial arts) back".[23]

On October 4, 2008, a Kimbo Slice vs. Ken Shamrock fight was supposed to take place at the BankAtlantic Center in Sunrise, Florida as part of CBS' Saturday Night Fights.[24][25] However, Shamrock received a cut to the left eye during a warm-up only hours before the fight was to take place.[26] This left the head of fight operations, Jeremy Lappen, to choose a replacement for the fight. Options were Seth Petruzelli, Aaron Rosa and Frank Shamrock. Slice's team stated they did not want him fighting Frank no matter how much money was offered to them, so Lappen decided that Petruzelli was the best option for the main event. Slice agreed to take the fight after receiving a raise in pay, and took in $500,000.[27] Petruzelli defeated Slice by TKO 14 seconds into the first round of the bout.[28]

Interviewed on Orlando radio show The Monsters in the Morning two days after the fight, Seth Petruzelli said that when they offered him a spot in the main event, EliteXC promoters added monetary incentives to dissuade him from using certain fighting techniques against Slice, in an attempt to protect their relatively unproven Internet star.

The promoters kinda hinted to me and they gave me the money to stand and throw with him, they didn't want me to take him down. Let's just put it that way. It was worth my while to try and stand up punch him.[29]

This added to the controversy surrounding the representation of Slice as a top flight martial artist by CBS and EliteXC.[30] The Florida Department of Business and Professional Regulation started a preliminary investigation on the events surrounding the fight and its outcome.[31]

However, Petruzelli retracted this statement a few hours later, claiming in a follow-up interview with MMA website FiveOuncesofPain.com that his previous comments on The Monsters had been misinterpreted.

What was meant to be said was that I wanted to keep the fight standing for myself because I knew that was what the crowd, the promoters, and everyone wanted to see because that's more exciting than just taking someone to the ground. That was my thing only. I wanted to keep it exciting so I decided to keep it standing. It had nothing to do with anybody else. That was all me.[32]

On October 23, 2008, the Florida Department of Business and Professional Regulation concluded its investigation of the bout and found no wrongdoing.[33] By the end of October 2008, EliteXC was forced to file for bankruptcy.[34] Many in the mixed martial arts community, including Jay Thompson, executive consultant to the company, attributed EliteXC and ProElite's failure due to Slice's loss to Seth Petruzelli.[35]

After Elite Xtreme Combat ceased operations, Dana White stated that if Slice wanted to compete in the Ultimate Fighting Championship he would have to win his way in by competing on The Ultimate Fighter TV show. White went on to say that he might create a show with heavyweights just for Kimbo Slice if he wanted in.[36] That statement became reality on June 1, when Kevin Iole of Yahoo.com stated Slice would participate in The Ultimate Fighter: Heavyweights.

The coaches for the show were Quinton Jackson and Rashad Evans, both former UFC Light Heavyweight Champions.[37] Slice was the number one pick for coach Rampage and the second pick overall. In his first fight of the show, Slice was defeated by Roy Nelson via TKO stoppage in the second round after repeated punches to the head in the crucifix position.[38] Slice later turned down the opportunity to take Matt Mitrione's place in the quarter finals after it was revealed that he had arthritis in his knee.

Slice fought Houston Alexander on December 5, 2009, at The Ultimate Fighter: Heavyweights Finale at a catchweight of 215 pounds.[39] In a fight that many thought would not leave the first round, Alexander would instead spend most of the first and third rounds circling Slice tentatively with little engagement. In the second round, however, Slice managed to land punches that visibly hurt Alexander, and even took him down a couple of times including slamming Alexander on his upper body, which very well may have tipped the judges' scorecards in his favor. Slice would win the bout by unanimous decision (29–28, 29–28, and 30–27) and Alexander would be cut from the promotion only days later.

On May 8, 2010, Slice made his pay-per-view and official heavyweight debut at UFC 113 versus Matt Mitrione, losing in the second round via a TKO.[40] Following the loss, Dana White stated that it was "probably Kimbo's last fight in the UFC".[41] His release was confirmed the following day, alongside welterweight Paul Daley.[42]

On January 16, 2015, nearly five years since his last MMA fight, Bellator MMA announced that Slice had signed a multi-fight deal.[3] He defeated Ken Shamrock by first-round TKO in his June 19 debut at Bellator 138.[43] Some observers noted the fight appeared to be fixed, like a professional wrestling match.[44][45] Bellator commentator Jimmy Smith accredited the fight looking as it did to Shamrock's lack of technique and durability, and said if it was fixed, Bellator wasn't in on the deal.[46]

On February 19, 2016, at Bellator 149, Slice faced Dada 5000. The duo had a big rivalry between them due to their old street fight legacies they had in Perrine, Florida. In the first round, both fighters gassed out almost immediately, and Slice went on to win an uneventful fight via TKO when Dada collapsed from apparent exhaustion in the third round.[47] Following the bout it was reported that Slice had failed his pre-fight drug test. Lab results found traces of the anabolic steroid nandrolone. He was also found to have an elevated testosterone/epitestosterone (T/E) ratio of 6.4:1, which is above the maximum allowed limit of 4:1. On May 2, 2016, it was revealed that Slice had settled with the Texas Athletic Commission with a fine of $2,500 and a revoking of his license in the state of Texas. The result of the bout has also been changed to a no contest.[48] Despite being widely panned by critics, the fight attracted approximately 2.5 million viewing households, breaking the Bellator record of 2.4 million, set by Kimbo vs Shamrock.[49]

In April 2016, Bellator President Scott Coker announced on ESPN's SportsCenter that Slice would have a rematch against James Thompson in the main event of Bellator 158, which would take place on July 16, 2016 at London's O2 Arena.[50] Slice died of heart failure before this fight could happen.