Drake, Magma (CR 13)

Large Dragon (Earth and Fire)
Alignment: Usually lawful evil
Initiative: +6 (+2 Dex, +4 Improved Initiative); Senses: darkvision 60 ft., low-light vision, tremorsense 60 ft., Spot +22, and listen +22
Languages: Draconic and either Ignan or Terran (50% chance of either)

AC: 23 (-1 size, +2 Dex, +12 natural), touch 11, flat-footed 21
Hit Dice: 16d12+64 (172 hp)
Fort +14, Ref +14, Will +11
Speed: 30 ft., burrow 10 ft., fly 60 ft. (poor)
Space: 10 ft./5 ft.
Base Attack +16; Grapple +26
Attack: Bite +21 melee; or claw +19 melee
Full Attack: Bite +21 melee and 2 claws +19 melee and tail slap +19 melee
Damage: Bite 2d6+6, claws 1d8+3, tail slap 1d8+9
Special Attacks/Actions: Improved grab, burn
Abilities: Str 23, Dex 14, Con 19, Int 8, Wis 12, Cha 11
Special Qualities: immunity to fire, magic sleep effects, and paralysis, vulnerability to cold
Feats: Alertness; Flyby Attack Improved Initiative; Lightning Reflexes; Multiattack; Power Attack
Skills: Bluff +19, Climb +27, Diplomacy +2, Hide +19, Intimidate +2, Search +18, Spot +22, and listen +22
Advancement: 17-19 HD (Large); 20-29 HD (Huge); 30-39 HD (Gargantuan); 40-51 HD (Colossal)
Climate/Terrain: Warm mountains
Organization: Solitary, pair, or cluster (3-6)
Treasure/Possessions: Standard

Source: Draconomicon

Burn (Ex): Those grappled by a magma drake must succeed on a DC 22 Reflex save or catch fire. The fire burns for 1d4 rounds (see Catching on Fire). A burning creature can take a move action to put out the flame (but not while grappled).

Improved Grab (Ex): To use this ability, a magma drake must hit a creature of its size or smaller with a claw attack. It can then attempt to start a grapple as a free action without provoking an attack of opportunity.

Skills: Magma drakes have a +2 racial bonus on Climb checks and on Hide checks.

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.

Fire Subtype

A creature with the fire subtype has immunity to fire. It has vulnerability to cold, which means it takes half again as much (+50%) damage as normal from cold, regardless of whether a saving throw is allowed, or if the save is a success or failure.