Oscar Gutierrez Rubio is a Mexican American professional wrestler signed to World Wrestling Entertainment. Gutierrez was trained by his uncle Rey Misterio, Sr. and wrestled early on in Mexico, where he learned the Lucha Libre high flying style that is used as his trade mark move. Gutierrez originally worked for Asistencia Asesoría y Administración in Mexico, from 1992 to 1995. Mysterio signed with Paul Heyman's Extreme Championship Wrestling (ECW) in 1995. Rey Mysterio, Jr. made his World Championship Wrestling (WCW) debut on June 16, 1996 at The Great American Bash, challenging Dean Malenko for the WCW Cruiserweight Championship. Mysterio later became a "giant killer" by defeating large opponents such as Kevin Nash, Bam Bam Bigelow, and Scott Norton. In March 15, at Nitro, he defeated Billy Kidman to win his fifth Cruiserweight Championship. In June 2002, Mysterio signed with World Wrestling Entertainment (WWE) and the "Jr." was dropped from his name and was billed simply as Rey Mysterio. In WCW he won the WCW World Tag Team Championship three times, and the WCW Cruiserweight Tag Team Championship once with Billy Kidman as part of the Filthy Animals. In WWE, Mysterio is a three-time world champion, having held the World Heavyweight Championship twice and the WWE Championship once, and is currently listed as the lightest world champion in WWE history. He has also held the WWE Tag Team Championship a record-tying four times, and the WWE Intercontinental Championship twice. He also held the WCW/WWE Cruiserweight Championship a record eight times. Mysterio is known for having a high flying style, which helped kick-start the cruiserweight wrestling revolution in the United States in the late 1990s during his time in WCW.