Incorporeal Movement.

The ghost dragon can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.

Legendary Resistance (3/Day).

If the ghost dragon fails a saving throw, it can choose to succeed instead.

Unusual Nature.

The ghost dragon doesn't require air, food, drink, or sleep.

Actions

Multiattack.

The ghost dragon makes one Bite attack and two Claw attacks.

Bite.

Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 32 (6d8 + 5) cold damage, and the target's speed is halved until the start of the dragon's next turn.

Claw.

Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 5) necrotic damage.

Terrifying Breath (Recharge 6).

The ghost dragon exhales shadowy mist in a 90-foot cone. Each creature in that area must make a DC 21 Constitution saving throw. On a failed save, the creature takes 40 (9d8) cold damage and is frightened of the ghost dragon for 1 minute. On a successful save, the creature takes half as much damage and isn't frightened.

While frightened of the ghost dragon, a creature is paralyzed. The frightened 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 this ghost dragon's Terrifying Breath for the next 24 hours.

Ghost Dragon