Rey Mysterio was a kickboxer.
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 . 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 , and is often regarded as one of the greatest high-flyers in wrestling history . In WWE , Mysterio is a three-time world champion , having held WWE 's World Heavyweight Championship twice and the WWE Championship once .