Amphibious. The dragon can breathe air and water.

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, unles the damage is radiant or from a critical hit. On a success the zombie drops to 1 Hit Point instead.

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

Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 15 (2d10 + 5) piercing damage plus 7 (2d6) necrotic damage.

Claw. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 5) slashing damage.

Rotting Breath (Recharge 5–6). The dragon exhales rotting gas in a 30-foot cone. Each creature in that area must make a DC 15 Constitution saving throw, taking 42 (12d6) necrotic damage on a failed save, or half as much damage on a successful one. A humanoid reduced to 0 hit points by this damage dies, and it rises as a zombie and acts immediately after the dragon zombie in the initiative count. The new zombie is under control of the creature controlling the dragon zombie.