Vigorous Shot

You fire a bolt of pure energy towards a target. The target must make a DEX saving throw. The DC of the saving throw is 1d20+your spellcasting modifier. If the target fails they take an amount of damage equal to the DC of the saving throw. On a success the target takes half damage. You may choose to re-roll the d20 and take the higher result, however, if you do you get disadvantage on your next attack roll. If the target fails the DEX saving throw, they must succeed a STR saving throw with a DC of half the DEX saving throw or be knocked prone.