Bloodletter

You slash or pierce your hand with your weapon, and draw essence from your blood, taking 1d4 of the respective damage. A nonmagical weapon you use to cast this spell becomes magical. Choose one of the following damage types: force, necrotic, psychic, or radiant. For the duration, the weapon deals an additional 1d6 damage of the chosen type when it hits.

At Higher Levels. When you cast this spell using a spell slot of 4th level, the weapon gains a +1 bonus to attack rolls and the extra damage increases to 2d6. When you use a spell slot of 6th level, the bonus to attack rolls increases to +2 and the extra damage increases to 3d6. When you use a spell slot of 8th level, the bonus to attack rolls increases to +3 and the extra damage increases to 4d6.