Undead Fortitude.

If damage reduces the zombie to 0 hit points, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is radiant or from a critical hit. On a success, the zombie drops to 1 hit point instead.

Actions

Bite.

Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 14 (4d6) piercing damage.

Eye Ray.

The zombie uses a random magical eye ray, choosing a target that it can see within 60 feet of it.

1. Paralyzing Ray. The targeted creature must succeed on a DC 14 Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
2. Fear Ray. The targeted creature must succeed on a DC 14 Wisdom saving throw or be frightened for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
3. Enervation Ray. The targeted creature must make a DC 14 Constitution saving throw, taking 36 (8d8) necrotic damage on a failed save, or half as much damage on a successful one.
4. Disintegration Ray. If the target is a creature, it must succeed on a DC 14 Dexterity saving throw or take 45 (10d8) force damage. If this damage reduces the creature to 0 hit points, its body becomes a pile of fine gray dust.If the target is a Large or smaller nonmagical object or creation of magical force, it is disintegrated without a saving throw. If the target is a Huge or larger nonmagical object or creation of magical force, this ray disintegrates a 10-foot cube of it.

Environment: Underdark

Beholder Zombie