Ooze, Bloodfire, Blighted (CR 12)

Huge Outsider (Augmented Ooze and Fire)
Alignment: Neutral Evil
Initiative: +1(Dex); Senses: blind, blindsight 60 ft., and Listen +0
Languages: -

AC: 17 (-2 size, +1 Dex, +8 natural), touch 9, flat-footed 16
Hit Dice: 12d8+108 (162 hp); DR: 10/magic
Fort +12, Ref +5, Will +4
Speed: 30 ft.
Space: 15 ft.; Reach 10 ft.
Base Attack +9; Grapple +24
Attack: Melee: slam +15 (2d6+10/19-20 plus 2d6 fire)
Special Attacks/Actions: alternate form, flame burst, negative energy ray
Attack Options: burning blood, magic strike, true strike 1/day
Abilities: Str 24, Dex 13, Con 26, Int 3, Wis 11, Cha 6
Special Abilities: Immune: fire, gaze attacks, illusions, visual effects; Resist: acid 15, electricity 15; SR 22 (27 against positive energy); Weakness: vulnerability to cold; fast healing 5
Special Qualities: empower fire spells, negative adaptation, ooze traits
Feats: Ability Focus (flame burst), Improved Critical (slam), Improved Natural Armor, Improved Natural Attack (slam), Weapon Focus (slam),
Skills: Escape Artist +16, Hide +8, Listen +0, Move Silently +16, and Sense Motive +15
Advancement: 13-24 HD (Huge); 25-48 HD (Gargantuan)
Climate/Terrain: Areas of evil or fire
Organization: None
Treasure: Standard

Source: Monster Manual IV