Stepping outside the world of classic rock for just a moment, a fan attending a NOFX show in Australia found out the hard way that not all musicians appreciate being grabbed while in the midst of a performance.

Vocalist Fat Mike had informed the crowd earlier during this Nov. 5 concert at Sydney that an injury had limited his mobility. “I hurt my neck somehow, really bad, so I can’t really move around very well," he said from on stage. "So, if you throw something at me again, I’m gonna really be pissed.”

No sooner had Fat Mike uttered the word "pissed" when he was clocked in the face with a flying piece of trash. Later in the show, a rambunctious fan (later idenitifed via the Twitter handle Alex) found his way on stage and put his arm around Fat Mike's neck.

The singer responded by elbowing Alex in the face, and then kicking him when he was on the ground.

The hostilities stopped there, however. After the concert, Alex tweeted Fat Mike, apologizing for surprising him in the manner he did. The vocalist replied with an apology of his own, stating his reaction was merely a matter of his defenses kicking in.

People were quick to admonish Fat Mike for his actions, although Alex continued defending the singer. He then posted what looks to be a final, definitive statement on the matter:

More From Ultimate Classic Rock