barrage of knifes

you cast 2d6 +3 knifes out of thin air, all the knifes point towards your target and fly 25 feet per sec at them. the target takes a dc 15 for dexterity. if they pass ,they get hit with only two but if they fail, they get hit with the full force. each knife deals 1d6-2 damage. if the knifes have been out for 3 mins or if you have died, they will disappear.