Disrupting Countersong

When a hostile creature you can see within range that can hear you uses a power or spell with a verbal, sonic, charm, fear, or psychic component, spend 1 charge and force it to make a CHA save. On a failed save, the power or spell fails and is wasted. On a success, the creature subtracts 1d10 from one attack roll or saving throw caused by that power or spell.