Hex

You place a curse upon a creature that you can see within range. Until the spell ends, you deal an extra 1d6 necrotic damage to the target whenever you hit it with an attack. Also, choose one ability score; the target has disadvantage on ability checks made with the chosen ability. If the target drops to 0 hit points before the spell ends, you can use a bonus action on a subsequent turn to curse a new creature. The curse manifests as a dark sigil that flickers on the target's forehead, invisible to most, but painfully apparent to anyone with the Sight. The necrotic damage is not mere energy; it is the erosion of the target's vitality, fed directly to you through the link of the hex.