Stench. Any creature that ends its turn within 5 feet of the zombie pig must succeed on a DC 15 constitution saving throw or be poisoned until the end of the zombie pig's next turn.

Undead Fortitude. If the zombie pig is reduced to 0 hit points, it must succeed on a constitution saving throw with a save DC equal to 10 + the damage taken. On a successful save, the zombie pig gains 1 hit point.

Death Burst. When the zombie pig dies, it explodes, and each creature within 15 feet of the zombie pig when it explodes must succeed on a DC 15 constitution saving throw, taking 13 (3d8) poison damage on a failed save, or half as much on a successful one.

Multiattack. The zombie pig makes up to 3 melee attacks, only one of which may be a gore attack.

Tusk. Melee Weapon Attack: +5 to hit, reach 5 ft., 1 target. Hit: 11 (2d8 + 2) piercing damage. 

Gore. Melee Weapon Attack: +5 to hit, reach 5 ft., 1 target. Hit: 15 (3d8 + 2) slashing damage.