Alabaster Dragon

Legendary Resistance (1/Day). If the dragon fails a saving throw, it can choose to succeed instead.

Ambush Predator. The dragon has advantage on any attack against a creature who has not yet taken their turn in initiative.

Multiattack. The dragon can use its Frightful Presence. It then makes two attacks: one with its bite and one with its claws. Alternatively, it can forgo the Frightful Presence and make four attacks: one with its bite, two with its claws, and one with its tail.

Bite. Melee Weapon Attack: +9  to hit, reach 10 ft., one target. Hit: 17( 2d8+8) piercing damage.

Claw. Melee Weapon Attack: +9  to hit, reach 10 ft., one target. Hit: 18 (3d6 + 7) slashing damage.

Tail. Melee Weapon Attack: +9  to hit, reach 10 ft., one target. Hit: 16 (1d12 + 9) 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 14 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.

Brittle Breath (Recharge 4–6);. The dragon exhales weakening gas in a 60-­foot cone. Each creature in that cone must make a DC 17 Constitution saving throw, becoming vulnerable to all damage until the end of the dragon's next turn on a failed save. On a successful save, the creature is unaffected.

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.

Hide. The dragon makes a Dexterity (Stealth) check.

Tail Attack. The dragon makes a tail attack.

Crumble (Costs 2 Actions). Any creature currently affected by the dragon's Brittle Breath loses 15 hit points.