Donnell Vannison

Donnell Vannison (March 27, 2012)

To view the video, scroll down.

A Baltimore man charged with assaulting a 16-year-old student on the campus of Long Reach High School, in Columbia, in March pleaded guilty to second-degree assault Monday and will serve 60 days in jail, according to Howard County State's Attorney's office spokesperson Wayne Kirwan.

Donnell Maurice Vannison, 40, of 1152 N. Longwood Street, was charged in connection with the March 21 incident after he came to Long Reach High School at 2:20 p.m., 10 minutes after the end of the school day, and assaulted a student, according to Howard County Police

Vannison, who has been incarcerated since July 31 for violating probation, will be credited for the 49 days already served, Kirwan said.

Police said Vannison put on a ski mask, approached the student and assaulted him. Vannison's blow grazed the student, who retaliated by knocking Vannison unconscious with one punch.

The incident, which lasted roughly 27 seconds, was captured on video by an onlooker and put on WorldStarHipHop.com, where it went viral.

Police said Vannison was unconscious for a short period of time before he left the school under his own power.

The male student was not charged, police said, because investigators believe he was acting in self defense.