Boar

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. !!! actions = !Tusk. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) slashing damage. [[/include]]

Source: Monsters Manual, p. 319