You have mastered the use of whips as deadly weapons through hours of practice. You gain the following benefits:

• When you use a whip, its damage die changes from a d4 to a d6 (this benefit has no effect if another feature has already improved the weapon’s die).

• When you hit with an opportunity attack using the whip, the target must succeed on a Dexterity saving throw (DC 8 + your proficiency bonus + your Strength or Dexterity modifier) or be knocked prone.