Bladethirst

The caster's sword or other slashing weapon bursts into unearthly steel-blue flame. Until the end of their turn, they have advantage on all rolls to hit with this weapon, inflicting an additional 1d6 cold damage on hit. The weapon sheds bright light in a 10-foot radius and dim light a further 10 feet.

At Higher Levels: When this spell is cast using a spell slot of 2nd level or higher, the damage is increased by 1d6 per slot level.