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 5-foot-diameter tunnel in its wake.

Actions

Bite.

Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (1d10 + 3) piercing damage plus 3 (1d6) thunder damage.

Debilitating Breath (Recharge 5–6).

The dragon exhales a pulse of high-pitched, nearly inaudible sound in a 15-foot cone. Each creature in that area must make a DC 13 Constitution saving throw. On a failed save, the creature takes 22 (4d10) 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:

1/day each: alarm, Tenser's floating disk

Sapphire Dragon Wyrmling