Brass Knuckles

You touch a willing creature. For the duration, their fists are magically enhanced, and the image of brass knuckles form on their fists. If the spell has not ended, your target may add your spellcasting ability modifier rather than their original ability modifier to the Unarmed Strike attack roll. Additionally, their unarmed strikes deal Force Damage equal to 1d4 + their Strength modifier. At the end of your target's next turn, this spell ends. 

At Higher Levels. When you cast this spell using a 2nd level spell slot or higher, the damage increases by 1d4 for each spell slot above 1st. When cast using a 4th level spell slot or higher, your target may make an additional unarmed strike on their turn.