Spell Disruptor Horn

This horn is carved with images of a Spellhound (see Tome of Beasts 2) and invokes the antimagic properties of the hound's howl. You use an action to blow this horn, which emits a high-pitched, multiphonic sound that disrupts all magical effects within 30 feet of you. Any spell of 3rd level or lower in the area ends. For each spell of 4th-level or higher in the area, the horn makes a check with a +3 bonus. The DC equals 10 + the spell's level. On a success, the spell ends. In addition, each spellcaster within 30 feet of you and that can hear the horn must succeed on a DC 15 Constitution saving throw or be stunned until the end of its next turn. Once used, the horn can't be used again until the next dawn.