Hex

You place a curse on a creature that you can see
within range. For 1 hour, you deal an extra 1d6
necrotic damage to the target whenever you hit it
with an attack. Also, choose one ability when you
cast the spell. The target has disadvantage on
ability checks made with the chosen ability.
If the target drops to 0 hit points before this spell
ends, you can use a bonus action on a subsequent
turn of yours to curse a new creature.