Dragon, Brown Ancient (CR 21)

Gargantuan Dragon (Earth)
Alignment: Usually neutral evil
Initiative: +0; Senses: blindsense 60 ft., darkvision120 ft., low-light vision, keen senses, and tremorsense 500 ft.
Languages: Draconic

AC: 36 (-4 size, +30 natural), touch 6, flat-footed 36
Hit Dice: 33d12+297 (511 hp); DR: 15/magic
Fort +27, Ref +18, Will +23
Speed: 60 ft., burrow 60 ft.
Space: 20 ft./15 ft. (20 ft. with bite)
Base Attack +33; Grapple +60
Attack: 1 Bite +44, 2 claws +39, 2 wings +39, 1 Tail Slap +39, 1 crush +39, 1 Tail sweep +39 melee; Breath +44 ranged
Damage: 1 bite 4d6+15, 2 claws 2d8+7, 2 wings 2d6+7, 1 tail slap 2d8+22, 1 crush 4d6+22, 1 tail sweep 2d6+22, Breath weapon 20d6 (35)
Special Attacks/Actions: Breath Weapon, fear (DC 31), SR 30
Abilities: Str 41, Dex 10, Con 29, Int 20, Wis 21, Cha 20
Special Qualities: Acid immunity, create water, sandstorm, summon Huge Air elemental, summon greater air elemental as 13th-level caster
Feats: #Feats: 12
Class Skills: Climb, Hide, Skill points: 171, and Survival
Advancement: 34-35 HD (Gargantuan)
Climate/Terrain: Any desert
Organization: Solitary, pair, or family (1-2 and 2-5 offspring)
Treasure/Possessions: Double Standard

Source: Monster Compendium: Monsters of Faerûn

Breath Weapon (Su): The brown dragon's breath weapon is a line of acid. It does not use this attack against mounted foes, since it knows that horses are good eating. Using a breath weapon is a standard action. Once a dragon breathes, it can't breathe again until 1d4 rounds later. A blast from a breath weapon always starts at the dragon's mouth and extends in a direction of the dragon's choice.

Tremorsense (Ex): Brown dragons can automatically sense the location of anything within 500 feet that is in contact with the ground.

Create Water (Sp): The dragon can use this spell-like ability once per day.

Sandstorm (Sp): Once per day, an adult brown dragon can create a vortex of violently churning sand at a distance up to 80 yards away. All creatures within a 60-foot radius of the center of the sandstorm take 1d6 points of damage each round they remain within the sandstorm. Characters in the swirling sands are blinded and must make a Balance check (DC 15) during each round they move more than 5 feet or fall prone.

Summon Huge Air Elemental (Sp): Once per day, an old brown dragon can cast summon nature's ally VI to summon one Huge air elemental, 1d3 Large air elementals, or 1d4+1 air elementals of smaller size.

Summon Greater Air Elemental (Sp): Once per day, an ancient brown dragon can cast summon nature's ally VIII to summon one greater air elemental, 1d3 Huge air elementals, or 1d4+1 air elementals of smaller size.

Frightful Presence (Ex): A young adult or older dragon can unsettle foes with its mere presence. The ability takes effect automatically whenever the dragon attacks, charges, or flies overhead. Creatures within a radius of 300 feet are subject to the effect if they have fewer HD than the dragon (33).

A potentially affected creature that succeeds at a Will save (DC 29) remains immune to that dragon's frightful presence for one day. On a failure, creatures with 4 or fewer HD become panicked for 4d6 rounds and those with 5 or more HD become shaken for 4d6 rounds.

Dragons ignore the frightful presence of other dragons.

Earth Subtype

This subtype usually is used for elementals and outsiders with a connection to the Elemental Plane of Earth. Earth creatures usually have burrow speeds, and most earth creatures can burrow through solid rock.