Ferocious Charger

Mounted Specialist: 15th level You can run down your foes, whether you're mounted or not. If you move at least 10 feet in a straight line right before attacking a creature and you hit it with the attack, that target must succeed on a Strength saving throw (DC = 8 + your proficiency bonus + your Strength modifier) or be knocked prone. You can use this feature only once on each of your turns.

Granted by Mounted Specialist at 15th level.