Rhinoceros

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.

Melee Weapon Attack: +7 to hit, reach 5 ft.. Hit: 14 (2d8 + 5) bludgeoning damage.