Boar

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.

1 use per short 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.

Melee Weapon Attack: +3 to hit, reach 5 ft.. Hit: 4 (1d6 + 1) slashing damage.