The whole thing was caught on tape in a shocking video shot inside a bus packed with high school students.
The video shows the heated moments before a violent altercation in Kenosha, CNN reports.
The driver reportedly told authorities he asked for the teen's information after allegedly experiencing issues with him on previous rides.
The teen is seen in the video taking his seat, but a few moments later, he approaches the front of the bus and pulls the first punch.
But, perhaps more shocking, the bus then crashes into three parked cars, one with people still inside, while no one is behind the wheel.
The teen is facing felony charges for assaulting the driver and reckless endangerment.
The driver declined to comment; his union rep is fighting for him to get his job back.
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