During the monumental defeat of Brazil on 8 July 2014, some people jokingly said on Twitter that Holland and Argentina should hope that the Brazil fans storm the field and lynch both teams (their own team for disappointing them so much and the Germans for revenge). Of course this would never happen because it would be terribly unsportsmanlike, not to mention a gigantic smear on the reputation of the country.
But what if that actually would have happened? What if the fans of a heavily losing team storm the field and attack the winning team, incapacitating some of their players? Does the FIFA have rules for such an occurence?