A student at Marjory Stoneman Douglas High School — the site of one of the nation’s worst mass shootings — was savagely beaten by a gang of teens in a brutal caught-on-video attack, which landed the youngster in hospital. The unidentified student was pummeled by at least a half dozen teen thugs before he was picked up and hurled onto the pavement head first near the Parkland, Florida campus — leaving him sprawled out motionless on the ground, video footage posted by TMZ on Wednesday shows.