Undead Fortitude. If damage reduces the dragon 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 dragon zombie drops to 1 hit point instead.

Multiattack. The dragon zombie makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) piercing damage.

Claw. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) slashing damage.

Breath Weapons (Recharge 5–6). The dragon zombie uses one of the following breath weapons.

Cold Breath. The dragon zombie exhales an icy blast in a 30-foot cone. Each creature in that area must make a DC 17 Constitution saving throw, taking 54 (12d8) cold damage on a failed save, or half as much damage on a successful one.

Paralyzing Breath. The dragon zombie exhales paralyzing gas in a 30-foot cone. Each creature in that area must succeed on a DC 17 Constitution saving throw or be paralyzed for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.