It's not unsual for tourists to pester the Queen's Guards, but now they're starting to fight back, or at least this Guard has.
Taken at Windsor Castle in England, the video shows a tourist mimicking a marching Queen's Guard and laughing obnoxiously, with the Guard paying him no attention. Emboldened by this, the young tourist starts to put his arm on the Guard's shoulder.
But that just pushes the Guard over the edge, as he turns to the tourist with his weapon drawn and yells "Step back from the Queen's Guard!"