Ken Shamrock is not only a veteran of the squared circle, he is also a veteran of the Octagon--he competed in Ultimate Fighting before becoming a wrestler. He is known for his powerful moves and his submission holds.
Shamrock stared out in the World Wrestling Federation as a guest referee at WrestleMania XIII for the Steve Austin vs. Bret Hart match. He then started to wrestle and won several titles, including the Intercontinental Championship and the Tag Team Titles with the Big Boss Man. Since an injury struck in 1999, Ken Shamrock has been out of wrestling.
Shamrock ended up on the debut episode for NWA TNA in 2002.