Amphibious. The dragon can breathe air and water.
Multiattack. The dragon makes three attacks: one with its bite and two with its claws.
Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 15 2d10+4 piercing damage plus 7 2d6 poison damage.
Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 2d6+4 slashing damage.
Poison Breath (Recharge 5-6). The dragon exhales poisonous gas in a 30-foot cone. Each creature in that area must make a DC 14 Constitution saving throw, taking 42 12d6 poison damage on a failed save, or half as much damage on a successful one.