Curse of Lilith

You place a curse on a creature that you can touch. Until the spell ends, you deal an extra 1d6 Necrotic damage to the target whenever you hit it with an attack roll. Also, the target receives a reduction to all rolls equal to your proficiency bonus

If the target drops to 0 Hit Points before this spell ends, you can take a Bonus Action on a later turn to curse a new creature.

Using a Higher-Level Spell Slot. Your Concentration can last longer with a spell slot of level 2 (up to 4 hours), 3–4 (up to 8 hours), or 5+ (24 hours).