Infection. The zombie carries an infectious disease it can spread to living creatures. The disease attack the creature's system, reducing it's Hit Points maximum by 3 (1d6) for every hour that passes after.

While reduced to below half it's maximum hit points by the disease, the creature has the Poisoned condition. If it's Hit Points maximum is reduced to 0 by the disease, it dies, and rises 1 hour later as an Infectious Zombie hostile to all living creatures.

Creatures immune to the poisoned condition are immune to this disease, and a lesser restoration spell or similar magic cures it. A cured creature 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.

Slam. Melee Weapon Attack : +4 to hit, reach 5 ft., one creature. Hit: 6 (1d8 + 2) bludgeoning damage, and the target is grappled (escape DC 12).

Bite. Melee Weapon Attack : +4 to hit, reach 5 ft., one creature. Hit: 7 (2d4 + 2) piercing damage. If the target is a creature, it is subjected to the following effect. Constitution Saving Throw : DC 13. Failure : The target becomes infected with the disease described in the Infection trait.

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