Leyland is best known for smoking Marlboro Reds (America's toughest cigarette) in the dugout during games. But that is only where his badassness begins. Here he is cursing out baseball's biggest prick, Barry Bonds. Leyland was managing the Pirates at the time and Bonds was the team's biggest star. But that matters not to Leyland because, as he says after, he's “the goddamn manager.”
Language in the video is a bit colorful, obviously.
Related: How great was Barry Bonds's moustache?