Óscar Gutiérrez (born December 11, 1974), better known by his ring names Rey Mysterio Jr, or simply Rey Mysterio, is a Mexican-American professional wrestler. He is best known for his long tenure in WWE from July 2002 to February 2015. He is also known for his work in Extreme Championship Wrestling (ECW), Asistencia Asesoría y Administración (AAA), and World Championship Wrestling (WCW). Gutierrez was trained by his uncle Rey Misterio, Sr., learning the high flying Lucha Libre style that has been his trademark.