Passive Perception 11
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Charge. If the rhinoceros moves at least 20 feet straight toward a target and then hits it with a gore attack on the same turn, the target takes an extra 9 (2d8) bludgeoning damage. If the target is a creature, it must succeed on a DC 15 Strength saving throw or be knocked prone.
Gore. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 5) bludgeoning damage.