Hold Breath. The dragon can hold its breath for up to 30 minutes.

Multiattack. The dragon makes three Rend attacks.

Rend. Melee Attack Roll: +8, reach 10 ft. Hit: 10 (2d4 + 5) Slashing damage plus 3 (1d6) Acid damage.

Acid Breath (Recharge 5–6). Dexterity Saving Throw: DC 15, each creature in a 30-foot-long, 5-foot-wide Line. Failure: 31 (9d6) Acid damage. Success: Half damage.

Deep Ambush. While burrowing within 10 feet of the surface, the brown dragon erupts (without spending movement) into a 10-foot square on the ground directly above it. Dexterity Saving Throw: DC 15, each creature within the area where the dragon emerges. Failure: The target is Restrained by rubble. A creature can use its action to free itself or another creature within its reach. Failure or Success: The target is pushed 5 feet to an unoccupied space of the brown dragon’s choice, and the area the dragon appears in is Difficult Terrain.