Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.

Aura of Chaos. If a creature ends their turn within 30 feet of the dragon, they must make a DC 20 Charisma Saving Throw. On fail, the creature must roll 2d6. Each die represents one of its Ability Scores in order (1 = Strength, 2 = Dexterity, 3 = Constitution, 4 = Intelligence, 5 = Wisdom, 6 = Charisma). The two Ability Scores rolled by the creature are swapped around until either until the end of combat, or a different score-changing effect occurs. If a creature passes the save, they are immune to the dragons' Aura of Chaos for the next 24 hours.

Multiattack. The dragon makes three attacks on its turn: one with its bite and two with its claws. It may choose to replace its Bite attack with a Tail attack.

Claw. Melee Weapon Attack: +12 to hit, reach 5 ft., 1 target. Hit: 18 (2d10 + 7) slashing damage.

Bite. Melee Weapon Attack: +12 to hit, reach 10 ft., 1 target. Hit: 14 (2d6 + 7) slashing damage.

Tail. Melee Weapon Attack: +12 to hit, reach 15 ft., 1 target. Hit: 16 (2d8 + 7) bludgeoning damage.

Chaotic Breath (Recharge 5-6). The dragon exhales a stream of chaotic energy in either a 90 foot line that is 5 feet wide, or a 40 foot cone. Creatures in range must make a DC 20 Constitution Saving Throw, taking 66 (12d10) Force damage on a failed save, or half as much on a success. Creatures who fail the save suffer from the effects of Wild Magic and must make a roll on the table.

The dragon can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creatures' turn. The dragon regains spent Legendary Actions at the beginning of its turn.

Detect. The dragon makes a Wisdom (Perception) check.

Tail Attack. The dragon may make a tail attack

Wild Magic (Costs 2 Actions). The dragon may force a creature it can see within 100 feet to make a DC 20 Wisdom Saving Throw. On failure, the target creatures suffers the effects of Wild Magic and must make a roll on the table. If the target creature succeeds on the roll, the dragon regains one spent Legendary Action, and the save DC increases by 1 until a creature fails the roll.

Battlefield Weirdness. When the dragon reaches certain HP thresholds, special effects occur based on the dragons' HP. These effects happen immediately after the dragon drops below the HP threshold, and before any other Attacks, Actions, or other effects occur.

Initiative Scramble (143 HP). An invisible pulse emanates from the dragon in all directions. All creatures must re-roll initiative and use their new roll for the rest of combat. The dragon has advantage on its roll.

Ability Adjustment (95 HP). The dragon momentarily expands it Aura of Chaos out to a range of 300 feet. All creatures in range must immediately roll the saving throw or suffer the effects of the aura.

Power Shift (48 HP). The dragon lets out a roar of pain. All creatures within 300 feet that can hear this roar roll a d6. On a roll of 1-3, the armor they wear and weapons they hold suffer a penalty of -1, -2, or -3, based on their roll. On rolls of 4-6, their armor and weapons instead gain a bonus of +1, +2, or +3 depending on their roll. These effects last until the end of combat. If any creature rolls a 4-6, the dragon gains a +2 to its attack and damage rolls until the end of combat.