Boar

Relentless (1/Day). If the boar takes 5 or less damage that would reduce it to 0 hit points, it is instead reduced to 1 hit point.

Tusk. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6+1) slashing damage. If the boar moves at least 20 feet straight towards the target before the attack the attack deals an extra 3 (1d6) slashing damage and the target makes a DC 11 Strength saving throw falling prone on a failure.