Jeffrey Cobb is an American professional wrestler and former amateur wrestler who, as of May 2025, is signed to WWE, performing on the SmackDown brand under the ring name JC Mateo. He is best known for his eight-year (2017–2025) tenure in New Japan Pro-Wrestling (NJPW), where he was a member of United Empire, a one-time NEVER Openweight Champion, and a three-time IWGP Tag Team Champion. Cobb also wrestled for various promotions, including Lucha Underground (as the masked wrestler Matanza Cueto) where he held the Lucha Underground Championship, Ring of Honor (ROH) where he won the ROH Television Championship, and Pro Wrestling Guerrilla (PWG) where he captured both the PWG World and World Tag Team Championships and won the 2018 Battle of Los Angeles. As an amateur wrestler, Cobb represented Guam at the 2004 Summer Olympics, where he served as the nation’s flag bearer and competed in the men’s light heavyweight freestyle category before transitioning to professional wrestling in 2009.