Vynlorian Chromatic Blade

You brandish the melee weapon used in the spell’s casting, which is enveloped by an energy of your choice.  Choose between Force, Fire, Cold, Lightning, Thunder, or Necrotic.  The next time you hit with an attack with this weapon, it deals 3d4 of the selected damage type in addition to its normal damage.

Using a Higher-Level Spell Slot. Add 2d4 for each spell slot level above 1.