Óscar Gutiérrez (born December 11, 1974), better known by his ring names REY MYSTERIO Jr, or just Rey Mysterio, is a Mexican-American professional wrestler who currently works for Lucha Underground. He is best known for his long tenure in WWE from July 2002 until February 2015. Gutierrez was trained by his uncle Rey Misterio, Sr., learning the high flying Lucha Libre style that has been his trademark. 619.