Dungeons and Dragons 5th Edition Monster Manual pg 319
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 3 (1D6) Slashing Damage. If the target is a creature, it must succeed on a DC 11 Strength Saving Throw or be knocked prone. Relentless (Recharge 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.
Tusk. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1D6+1) Slashing Damage