Amphibious. The dragon can breathe air and water.

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

Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 10 (2d6 + 4) piercing damage plus 3 (1d6) acid damage.

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 4) slashing damage plus 3 (1d6) poison damage.

Breath Attack (Recharge 5–6).

The dragon can choose between two different breath attacks.

Acid Breath. 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 21 (7d6) acid damage on a failed save, or half as much damage on a successful one.

Poison Breath. The dragon exhales poisonous gas in a 30-foot cone. Each creature in that cone must make a DC 14 Constitution saving throw, taking 21 (7d6) poison damage on a failed save, or half as much damage on a successful one.

Grow Underlings. The dragon causes (1d4+2) Swamp Underlings to spring up from the ground within 150 ft of him.

The dragon can take 2 legendary action at the end of another creature's turn. The dragon regains the spent legendary action at the start of its turn.

Movement. The dragon moves up to his speed without provoking opportunity attacks.

Claw Attack. The Dragon makes one claw attack.

(Cost 2) Spellcasting (1/day each). The dragon casts stinking cloud or blindness/deafness at 4th level, targeting 3 creatures. Charisma is his spellcasting ability (spell save DC 14).