James "Clubber" Lang (born May 21st, 1958), also nicknamed The Southside Slugger, is an American former professional boxer who competed in the Heavyweight division during the 1980s. He reigned as the undisputed heavyweight champion and acts as the main antagonist in Rocky III and flashback antagonist in Rocky IV and Rocky V.
Lang rose to prominence in 1981 (Rocky III), storming through the ranks and defeating all challengers, Lang accumulated a record of 27-0 before challenging then heavyweight champion Rocky Balboa to a fight, Balboa accepted, and Lang knocked him out in the second round to become undisputed heavyweight champion. Balboa would receive a rematch, following training from former heavyweight champion Apollo Creed. Balboa would knock Lang out and regain his heavyweight championship, giving Lang his first defeat.
Clubber Lang participated in title eliminator bout in 1985 to become heavyweight champion once again, after Rocky had vacated the title to fight Ivan Drago in Russia. He lost in his first title defense to Union Cane in 1986.