spell stopper

when you hit a spellcaster with an attack once per turn you can choose to punch them in the throat hindering their spell casting abilities, when you hit them with a melee attack you can choose to make them roll a con save against your dc (8 + prof + dex/strength) if they fail they take an extra 1d4 bludgeoning damage and cannot cast spells untill the end of their next turn. you can use this feature up to a number of times equal to your strength/dex + monk/fighter level per long rest.