Amphibious. The dragon can breathe air and water.

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 makes three attacks: one with its bite and one with its claws.

Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 7 (1d10 + 2) piercing damage plus 4 (1d8) acid damage.

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) slashing damage.

Acid Breath (Recharge 5–6). The dragon exhales acid in a 30­-foot line that is 5 feet wide. Each creature in that line must make a DC 14 Dexterity saving throw, taking 49 (11d8) acid damage on a failed save, or half as much damage on a successful one.