You draw forth the ebbing life force of a creature and use it to fuel your own power. When a creature you can see within 5 feet of you dies, you gain 1d8 temporary hit points and your weapon attacks deal 1d4 extra damage. In addition, the next spell you cast before the end of your next turn is cast as if you used a spell slot one level higher.

At Higher Levels. You gain an additional 1d8 temporary hit points, the extra damage from your weapon attacks increases by an additional 1d4 and the next spell you cast before the end of your next turn is cast as if you used a spell slot one additional level higher for every two slot levels above 2nd you use to cast this spell.