In the wild, the gulo gulo (commonly called the wolverine) is a ferocious little beast capable of killing prey (and even predators) almost twice his size. And when trapped in a cage, he becomes even nastier — just like five-foot-ten lightweight dervish Mike "the Wolverine" Rio. After proving his relentlessness and grit as a two-time Florida state wrestling champ out of Miami Southridge High School, Rio tore into a pro career with a furious six-fight win streak, ripping through a mess of regional opponents by TKO and rear-naked choke. In 2011, though, he suffered his first career defeat in a Championship Fighting Alliance decision loss to Mexican grappler Efraín Escudero, the Ultimate Fighting Championship's Ultimate Fighter 8 winner. Still, the Wolverine had not been tamed. And over the past two years, he has clawed his way through a stint on the Ultimate Fighter 15 (failing to qualify for the finale only because of two broken ribs), inked a UFC contract, and notched another three wins. In December 2012, Rio made his debut in the octagon against John Cofer and snatched up the victory by cranking his victim's arm till he cried out, tapped, and quit. Yet even as a submission specialist, this 155-pound beast has won four of his nine career wins by KO. And that's what makes Rio so dangerous. He's equally vicious rolling on the floor and throwing punches. Maybe he'll snap his prey's limbs. Or maybe he'll just knock him the hell out. Either way, the Wolverine almost always wins.