Multiattack

The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.

Bite

Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 18 (3d6 + 8) plus 3 (1d6) poison damage.

Claw

Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 15 (2d6 + 8) slashing damage.

Tail

Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 17 (2d8 + 8) bludgeoning damage.

Frightful Presence

Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 18 Wisdom saving throw or become frightened 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. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.

Poison Breath (Recharge 5-6)

The dragon exhales a cone of black poison gas in a 60-foot cone. Each target in that area takes 56 (16d6) poison damage and is poisoned if it is a creature; a successful DC 18 Constitution saving throw reduces damage by half and negates the poisoned condition. The poisoned condition lasts until the target takes a long or short rest or it's removed with lesser restoration or comparable magic.