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