Fortune's Friend (1/Day). When the dragon makes an attack roll, a saving throw, or an ability check, the dragon can treat the roll as a natural 20.

Legendary Resistance (2/Day). If the dragon fails a saving throw, it can choose to succeed instead.

Multiattack. The dragon makes three attacks, one with its bite and two with its claw.

Bite Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 19 (2d10 + 7) piercing damage.

Claw Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 14 (2d6 + 7) slashing damage.

Tail. Melee Weapon Attack: +12 to hit, reach 15 ft., one target. Hit: 17 (2d8 + 7) bludgeoning damage.

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

Good Luck Breath. The dragon exhales a cloud of good luck particles in a 60-foot cone. For 1 minute, whenever a target makes an attack roll or a saving throw before the spell ends, the target can roll a d4 and add the number rolled to the attack roll or saving throw.

Bad Luck Breath. The dragon exhales a cloud of bad luck particles in a 60-foot cone. Each creature in that area must make a DC 18 Charisma saving throw, taking 33 (6d10) force damage on a failed save, or half as much damage on a successful one. Additionally or 1 minute, whenever a target that fails this saving throw makes an attack roll or a saving throw, the target must roll a d4 and subtract the number rolled from the attack roll or saving throw. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

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 creature's turn. The dragon regains spent legendary actions at the start of its turn.

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

Tail Attack. The dragon makes a tail attack.

Siphon Luck (Costs 2 Actions). The dragon emits an aura of bad luck. Each creature within 10 feet of the dragon must succeed on a DC 18 Charisma saving throw or take 14 (2d6 + 5) force damage and have disadvantage on their next ability check, attack roll, or saving throw. The dragon gains advantage on its ability check, attack roll, or saving throw.