Blasting Smite

Your currently held weapon begins to vibrate with energy. As you hit a creature with a melee weapon attack during this spell's duration, that energy is released. The target creature and all creatures within a 20-foot cone originating from it  must make a Dexterity Saving Throw, taking 2d8 force damage on a failure or half as much on a success.

* - Which you take immediately after hitting a target with a Melee weapon or an Unarmed Strike

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the force damage dealt increases by 1d8 and the cone size increases by 10ft for each slot level above 1st.