Charge. If the boar moves at least 20 feet in a straight line towards a creature before hitting it with a gore attack, the creature takes an additional 2d8 damage (included in the attack).

Driveby. The boar doesn't provoke attacks of opportunity when moving out of a creatures attack range unless it's speed has been reduced to 25 or less. 

Trample. The boar can move through the spaces of medium or smaller creatures provided it does not end its turn there, when it does so the creature must make a DC 17 strength or dexterity saving throw, taking 14 (4d6) bludgeoning damage and being knocked prone on a failed save.

Regeneration. The boar regains 20 hit points at the start of its turn. If the boar takes damage from a silvered weapon or ammunition, this trait doesn't function at the start of the boar's next turn. The boar dies only if it starts its turn with 0 hit points and doesn't regenerate.

Vorpal Tusks. When the boar lands a critical hit with its gore attack it deals an additional 4d8 force damage (included in the attack) If this would reduce to target to or below half their hitpoints, the targets head if they have one is severed from the body.

Tusk. Melee Weapon Attack: +9 to hit, reach 10 ft., 1 target. Hit: 23 (4d8 + 5) Piercing damage, plus 2d8 if charge. This attack critically hits on a roll of 18 or higher, and adds an additional 4d8 force damage after the critical damage is rolled.

Hooves. Melee Weapon Attack: +9 to hit, reach 10 ft., 2 targets. Hit: 27 (4d10 + 5) bludgeoning damage. If this attack is used the boars movement becomes 20 for the turn, only usable if the boar has not moved more than 20 feet this turn..