Flying knees appear to be the recent weapon of choice for combat wrestlers. Andre Harrison ’s opponent Thursday at PFL 5, Movlid Khaibulaev , is coming off a 10-second knockout of Damon Jackson at PFL Week 2, a spectacular, highlight-reel finish. A couple months later at UFC 239, Jorge Masvidal scored a record-breaking flying knee knockout over Ben Askren in just five seconds, and it seems like everybody is talking about the flying knee as a perfect counter strike for when a wrestler decides to shoot.