WATCH: Sen. Mullin Challenges Teamster President To Fight “Stand Your Butt Up”

A US Senator brought a very “meet me in the parking lot after school” vibe to a committee hearing Tuesday.

Sen. Markwayne Mullin (R-Okla.) and Teamsters General President Sean O’Brien challenged each other to a physical fight during the Senate HELP Committee with Sen. Bernie Sanders (I-Vt.) having to step in.

The two have a history of going after one another. Earlier in the year O’Brien called out Sen. Mullin in another meeting, stating the senator had engaged in fraud with his own company and that unions hold “greedy CEOS like yourself accountable.”

O’Brien joined several other union leaders to speak with the Senate Health, Education, Labor and Pensions (HELP) Committee Tuesday. It was during this time, Sen. Mullin brought up several negative tweets the Teamster chief had made towards the senator.

Sen. Mullin brought up one particular post from O’Brien that really heated up the room. The senator referenced a tweet where O’Brien told him to “quit the tough guy act” adding “you know where to find me, any place, anytime cowboy.”  With that, an invisible ringside bell was rung.

In front of the room, Mullin looked at O’Brien stating “Sir, this is a time, this is a place. You wanna run your mouth, we can be two consenting adults; we can finish it here.”

The heated back and forth escalated quickly, with Mullin demanding O’Brien “stand your butt up then.” O’Brien returned the antics with “you stand your butt up.”

Sen. Bernie Sanders, who is the chair of the committee, immediately put a stop to the juvenile behavior, asking if this is how a senator should act. Mullins simply replied “I’m still a guy.”

We may not know who would’ve won that fight, but one thing is clear O’BRIEND IS NOT INVITED TO MULLIN’S BIRTHDAY PARTY!