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.
Multiattack. The zombie uses Eye Rays twice.
Bite. Melee Attack Roll: +5, reach 5 ft. Hit: 16 (4d6 + 2) Piercing damage.
Eye Rays. The zombie randomly shoots one of the following magical rays at a target it can see within 120 feet of itself (roll 1d4; reroll if the zombie has already used that ray during this turn):
1: Paralyzing Ray. Constitution Saving Throw: DC 14. Failure: The target has the Paralyzed condition and repeats the save at the end of each of its turns, ending the effect on itself on a success. After 1 minute, it succeeds automatically.
2: Fear Ray. Wisdom Saving Throw: DC 14. Failure: 13 (3d8) Psychic damage, and the target has the Frightened condition until the end of its next turn.
3: Enervation Ray. Constitution Saving Throw: DC 14. Failure: 10 (3d6) Necrotic damage, and the target has the Poisoned condition until the end of its next turn. While Poisoned, the target can't regain Hit Points. Success: Half damage only.
4: Disintegration Ray. Dexterity Saving Throw: DC 14. Failure: 27 (5d10) Force damage. If the target is a nonmagical object or a creation of magical force, a 10-foot Cube of it disintegrates into dust. Success: Half damage. Failure or Success: If the target is a creature and this damage reduces it to 0 Hit Points, it disintegrates into dust.