Giant Boar

Charge. If the boar moves at least 20 ft. 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.

Tusk. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) slashing damage.