Barrage of Boulders
Sorcery
Barrage of Boulders deals 1 damage to each creature you don't control.
Ferocious — If you control a creature with power 4 or greater, creatures can't block this turn.
Crude tactics can be effective nonetheless.
Illustrated by
Khans of Tarkir#100CommonEnglishLegality
Rulings
Barrage of Boulders deals damage only to creatures you don’t control as it resolves. However, the ferocious ability affects all creatures, including ones you control and ones that weren’t on the battlefield as Barrage of Boulders resolved.
Some ferocious abilities that appear on instants and sorceries use the word “instead.” These spells have an upgraded effect if you control a creature with power 4 or greater as they resolve. For these, you only get the upgraded effect, not both effects.
Ferocious abilities of instants and sorceries that don’t use the word “instead” will provide an additional effect if you control a creature with power 4 or greater as they resolve.