Coup de Grace

Make a ranged spell attack against a single living creature you can see within range. If that creature has 5 or fewer hit points, they must make a Constitution save or drop to 0 hit points instead.  If the target is unconscious, it takes one death save failure immediately and has disadvantage on its next death save. If a target is killed by this spell while you are within 30 feet of it, you gain 2 temporary hit points. This spell has no effect against undead or constructs.