Thundering Punch

You channel magic into your Faulty Thunder Gauntlet. The gauntlet hums faintly with vibration.

The touch of your ultrasonic-wreathed hand shakes a target to it's core and creates unhearable soundwave tethers to their limbs. Make a melee spell attack against a creature within your reach. On a hit, the target takes 1d8 Thunder damage. Until the end of your next turn, the hit creature has advantage on attacks against you, but disadvantage on attacks against any other targets. Until the spell ends, you can make the attack again on each of your turns as an action.

Using a Higher-Level Spell Slot. The damage increases by 1d8 for each spell slot level above 1.