Boaroak

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 7 (2d6) slashing damage. If the target is a creature, it must succeed on a DC 13 Strength saving throw or be knocked prone.

Relentless (Recharges after a Short or Long Rest). If the boar takes 10 damage or less that would reduce it to 0 hit points, it is reduced to 1 hit point instead.

False Appearance: while it is not moving the creature is indistinguishable from a normal fallen over tree or bundle of vines and branches.

Reckless. the Boaroak can make an attack at advantage but will allow all other creatures to make their attacks at advantage until the beginning of the Boaroak's next turn. 

Multiattack. The Boaroak can make two attacks one with its goring tusks and a stomp attack.  or cast the entangle spell

Goring Tusk. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 10 (2d6 + 5) slashing damage. plus an extra 2 (1d4) piercing damage

Stomp. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit 9 (2d4+5) bludgeoning damage.

Entangle (1/day). The Boaroak can cast the entangle. Strength check to break Strength save DC 13

Thorns and Shrubbery. as a reaction if a creature does more than 10 points of damage, to the Boaroak. Every creature within 10ft of the Boaroak must make a Dexterity Saving throw DC 13 otherwise taking 7 (2d8) piercing damage on a failed save. Or half as much on a successful one. if the creature takes Fire damage on this turn it cannot use this ability.