Battle Boar

Charge. If the boar moves at least 20 feet straight toward a target and then hits it with a tusk attack on the same turn, the target takes an extra 9 (3d6) slashing damage. If the target is a creature, it must succeed on a DC 14 Strength saving throw or be knocked prone.

Relentless (Recharges after a Short or Long Rest). If the boar takes 7 damage or less that would reduce it to 0 hit points, it is reduced to 1 hit point instead.

Spiked Armor. Any creature that strikes the battle boar with a melee weapon attack takes 3 (1d6) piercing damage. 

Tusk. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (3d6 + 4) slashing damage.

Squeal (1/Day). The battle boar lets out a loud squeal that can be heard from 300 ft away. Battle boars, Large boars, and Tusk Bandits in the surrounding area come to its aid.