High School Senior Prank Flash Mob Turns Ugly [Video]

It's the end of the school year, which means time for high school senior pranks. This time, students at a school in San Antonio injured a teacher after attempting a prank. The flash mob started out with students chanting and yelling in the hallways, but then it got out of control and three kids were arrested for the incident. Check out the video to see how it goes wrong.