Bloodline - Bloodlust

You touch a weapon and invoke its thirst for blood. Until the spell ends, when an attack with that weapon hits, its wielder can spend 1 hit die and take 1 damage, and the weapon deals additional necrotic damage equal to the number rolled on the spent hit die.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the maximum hit dice that can be used increases by 1 for each spell level higher than 1st.