Corrupt 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 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 (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.

Corrupt Tusk. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 8 (2d6 + 1) slashing damage plus 1d4 poison damage at the start of the players turn, the player may choose to make a DC 15 Constitution save. On a successful save the player is cured of the poison, on a failed save the player takes an extra 1d4 poison damage straight away. 

 Battle Rage. The boar enters a frenzied state that lasts until the end of its next turn. During this time the boar has an advantage on all Wisdom (Perception) checks that rely on smell or sight. The boar also gains an advantage on all attack rolls it makes on a player within 10ft that it can see.  As well as this during this period of time, the boar has resistance against all piecing, slashing and bludgeoning damage