Know what would be a cool ability?

Something like jhins ult but instead of being able to shoot stuff the area inside the ult would be filled with a gas that causes a fog of war effect ( You can't see whats going on inside the gas/mist/fog or w/e ) and players inside said fog can't ping or use summoner spells maybe add a poison effect or a area wide debuff to all inside ult ( Spells do 5% less or something )