Infection. The zombie carries a magical infectious disease it can spread to living creatures. Creatures immune to the Poisoned condition are immune to this disease.

While infected, a creature has the Poisoned condition, and it's Hit Points maximum is reduced by 3 (1d6) every hour that passes after being infected. If it's Hit Points maximum is reduced to 0 by the disease, it dies, rising 1 hour later as an Infectious Undead hostile to all living creatures. if it dies from another source, it rises 1 hour later all the same.

A Lesser Restoration spell, Remove Curse spell, or similar magic cures an infected creature, which becomes Immune to the disease for 24 hours and has it's Hit Points maximum restored after it finishes a long rest.

Undead Fortitude. If damage reduces the zombie to 0 Hit Points, it makes a Constitution saving throw (DC 5 plus the damage taken) unless the damage is Radiant or from a Critical Hit. On a successful save, the zombie drops to 1 Hit Point instead.

Enraged. The zombie has Advantage on all melee weapon attack rolls relying on strenght, but attack rolls against it are made with Advantage. The zombie also has Advantage on strenght checks and saving throws.

Multiattack. The zombie makes two Slam attacks, one of which it can replace by a Bite attack.

Slam. Melee Weapon Attack : +9 to hit (with Advantage), reach 10 ft., one target. Hit : 20 (4d6 + 6) Bludgeoning damage.

Bite. Melee Weapon Attack : +9 to hit (with Advantage), reach 5 ft., one creature. Hit : 9 (1d6 + 6) Piercing damage and 7 (2d6) Poison damage. If the target is a creature, it is subjected to the following effect : Constitution Saving Throw, DC 15, Failure : The target becomes infected. Success : The target has Advantage on saving throws against that disease for 24 hours.

Boulder Toss (Recharge 5-6). The zombie hurls a boulder at a point it can see within 90 feet. Dexterity Saving Throw, DC 17, each creature in a 5-foot-radius Sphere centered on that point, Failure : 21 (6d6) Bludgeoning damage. If the target is a Large or smaller creature, it has the Prone condition. Success: Half damage only.

Aggressive. The zombie can move up to its speed toward a hostile creature that it can see.