Benefit: A barbarian’s mount can affect creatures up to its own size with its ferocious trample. In addition, it can make an overrun combat maneuver check as a free action against a creature that fails its Reflex save (or chooses not to save in order to take an attack of opportunity) against its trample.
Ferocious Trample, Greater (Ex)
Section 15: Copyright Notice
Advanced Player’s Guide. Copyright 2010, Paizo Publishing, LLC; Author: Jason Bulmahn.