Kimbo Slice, the bearded street fighter who parlayed his internet popularity into a mixed martial arts career and worldwide fame, has died aged 42.
Slice, whose real name was Kevin Ferguson, was taken to a hospital in Margate, Florida, near his home on Monday, Coral Springs Police said.
Mike Imber, Slice's longtime manager, confirmed his death in a message to Associated Press, saying: "We lost our brother today".
The cause of death was still unclear and police said no investigation has been launched as yet, and foul play isn't suspected.
Slice was a Bahamian-born ex-football player and strip club bouncer who began competing in unsanctioned street fights in 2003. Videos of his violent knockout victories in those bouts became wildly popular online, both for his punching power and his distinctive, intimidating appearance.
He studied MMA and eventually competed in several promotions, including the UFC and Bellator, which staged his two most recent fights.
Slice's death also was confirmed by Scott Coker, the CEO of Bellator, which promoted his return to MMA last year after a five-year absence. Slice beat Dhaffir "Dada 5000´´ Harris with a third-round knockout at Bellator 149 in February in Houston, but the result was overturned after Slice tested positive for steroid use.
"We are all shocked and saddened by the devastating and untimely loss of Kimbo Slice," Coker said.
"One of the most popular MMA fighters ever, Kimbo was a charismatic, larger-than-life personality that transcended the sport. Outside of the cage he was a friendly, gentle giant and a devoted family man. His loss leaves us all with extremely heavy hearts."
Slice was scheduled to headline the Bellator 158 show in London next month in a bout against James Thompson.
American Top Team, the prominent South Florida gym where Slice trained for many years, also mourned his passing.
"The ATT Family and South Florida community lost a legend today," the team said in a post on its Twitter account.
Slice was the star of the first MMA show broadcast on network television, beating Thompson by third-round knockout in May 2008 on CBS with the defunct EliteXC promotion. With Slice and pioneering featherweight Gina Carano as the top attractions, EliteXC's two CBS shows drew big television ratings and introduced millions of viewers to MMA.
While he went 5-2 and never won a championship belt, Slice became one of MMA's best-known figures, attracting large television audiences and crowds to his growing sport. He also had a pro-boxing career between stints in the cage, going 7-0 with six knockouts from 2011-13.
For all of his glowering in-cage swagger and viral fame, Slice was extraordinarily honest about his fighting abilities. He acknowledged being an MMA newcomer with much to learn about his new sport, never claiming to be anything but a big puncher providing for his family while constantly trying to learn the sport's other disciplines.
"The guys who are holding the titles, heavyweight and light heavyweight, these guys are awesome,"
Slice told AP in a 2010 interview before his second UFC fight. "I'm really just having happy days in the midst -- being among them, fighting on the undercards, just contributing to the UFC and the sport. That's really what I want to do. I'm not looking ahead to winning a title or anything like that. I'm just enjoying each fight as it comes."