Sure Footed

The Dragon has advantage on Strength and Dexterity saving throws made against effects that would knock it prone

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.

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) slashing damage.

Breath Weapons (Recharge 5-6). The dragon uses one of the following breath weapons:

Lightning Breath. The dragon exhales lightning in a 60-foot line that is 5 feet wide. Each creature in that line must make a DC 15 Dexterity saving throw, taking 40 (9d8) lightning damage on a failed save, or half as much damage on a successful one.

Charming Breath. The dragon exhales gas in a 30-foot cone. Each creature in that area must succeed on a DC 15 Constitution saving throw. On a failed save, the creature is charmed by the dragon for 1 minute, regarding the dragon as a trusted friend to be heeded and protected. Although it isn't under the dragon's control, it takes the dragon's requests and actions in the most favourable way it can.
Each time the dragon or the dragon's companions do anything harmful to an affected creature, it may repeat the saving throw, ending the effect on itself on a success.