Lightning Shard

The wrath of storm-scarred steel is fearsome to behold.
The first time you take the Attack action during your turn, you can cast this spell to infuse your melee weapon with elemental lightning, scorching and honing it to a razor edge. The first time you hit with this weapon, the target takes an additional 1d6 slashing damage, and the static within the blade discharges. The target must make a Constitution saving throw. If they fail, the target and up to two creatures of your choice within 10 feet of the target take 1d6 lightning damage.

At Higher Levels: When you cast this spell using a spell slot of 2nd level or higher, the either the slashing or lightning damage (your choice) increases by 1d6 per slot level above 1st.