Dwarven Shield Master

You use shields not just for protection but also for offense. You gain the following benefits while you are wielding a shield:

• If you take the Attack action on your turn, you can use a bonus action to try and make a special Shield Bash attack with your shield. You are proficient with this attack and it uses your Strength modifier, and on a hit it deals 1d4 + your Strength modifier in bludgeoning damage. In addition the target must succeed in a Strength saving throw equal to 8 + your proficiency bonus + your Strength modifier or be Stunned.
• If you aren't incapacitated, you can add your shield's AC bonus to any Dexterity saving throw you make against a spell or other harmful effect that targets only you.
• If you are subjected to an effect that allows you to make a Dexterity saving throw to take only half damage, you can use your reaction to take no damage if you succeed on the saving throw, interposing your shield between yourself and the source of the effect.