Eldritch Hex

You place a curse on 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 attack.  Also, choose one ability when you cast the spell.  The target has Disability 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.

A remove curse cast on the target removes this spell early.