Spider Climb.

The dragon can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Tunneler.

The dragon can burrow through solid rock at half its burrowing speed and can leave a 10-foot-diameter tunnel in its wake.

Actions

Multiattack.

The dragon makes one Bite attack and two Claw attacks.

Bite.

Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 16 (2d10 + 5) piercing damage plus 4 (1d8) thunder damage.

Claw.

Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 8 (1d6 + 5) slashing damage.

Debilitating Breath (Recharge 5–6).

The dragon exhales a pulse of high-pitched, nearly inaudible sound in a 30-foot cone. Each creature in that area must make a DC 17 Constitution saving throw. On a failed save, the creature takes 33 (6d10) thunder damage and is incapacitated until the end of its next turn. On a successful save, the creature takes half as much damage and isn't incapacitated.

Spellcasting (Psionics).

The dragon casts one of the following spells, requiring no spell components and using Intelligence as the spellcasting ability (spell save DC 15):

1/day each: dissonant whispers, hold person, meld into stone

Young Sapphire Dragon