Check out this incredible Kimbo Slice loses video. Sean Gannon and Kimbo Slice duke it out in an underground fight in what looks to be a converted H&R Block. These two titans wail on each other until they are both left bloodied and battered. MMA underground fights like these are bare-knuckle beat-downs that can go on for tens of minutes. But not when Sean Gannon is involved. Then we get a great Kimbo Slice video.