Cacus

A fire-breathing giant who eats human flesh and nails the heads of men to the door of his cave. Cacus was a fire-breathing monster and the son of Hephaestus. He lived in a cave in the Aventine Hill in Italy, the future site of Rome. He was eventually overcome by Heracles.

Heracles stopped to pasture the cattle he had stolen from Geryon near Cacus’ lair. As Heracles slept, the monster took a liking to the cattle and slyly stole eight of them dragging them by their tails, so they left no trail. When Heracles awoke he drove his remaining cattle past the cave, where Cacus was hiding the stolen ones, and they began calling out to each other.

Angered, Heracles stormed towards the cave. A terrified Cacus blocked the entrance with a vast, boulder, forcing Heracles to tear at the top of the mountain to reach his adversary. Finally Cacus attacked Heracles by breathing fire and smoke, Heracles responded by leaping into the cave and strangling the Giant.

Taken from Creature Codex

This giant humanoid towers taller than a house. His thick hide appears scorched and stained with soot and he clutches an enormous axe in his meaty paws. Two black-scaled serpents grow from its shoulders, probing the air with their forked tongues.

Thuggish brutes, the giant creatures known as cacuses prey on all those weaker than themselves. Most cacuses make their living as bandits and robbers, preferring to steal livestock than hunt for themselves and robbing caravans and coaches for their wealth. Each cacus maintains a wide territory on which to exploit, only associating with others of their own species for mating or especially ambitious schemes. Cacuses enjoy bullying weaker creatures into serving them, favoring giants for this purpose.

It is said that once cacuses were beloved by the gods, but have been cursed by their greed. The snakes that grow from their shoulders are the manifestation of this disfavor—each serpent has its own separate personality and often drives the cacus to ever-more-extravagant cruelty. These serpents also grant the cacus remarkable senses, allowing it to pinpoint creatures disabled by their choking smoke and track their prey by scent.

A cacus grows to twenty feet tall and weighs 8 tons.

Cacus     CR 12
XP 19,200
CE Huge monstrous humanoid
Init +6; Senses blindsense 60 ft., darkvision 60 ft., Perception +20, scent
Defense
AC 28, touch 10, flat-footed 26 (-2 size, +2 Dex, +4 armor, +14 natural)
hp 161 (14d10+84)
Fort +10, Ref +10, Will +12
Immune fire, poison
Offense
Speed 30 ft. (40 ft. unarmored)
Melee greataxe +21/+16/+11 (4d6+13/19-20×3), 2 bites +16 (1d6+4 plus poison) or 2 slams +21 (1d8+9), 2 bites +21 (1d6+9 plus poison)
Ranged flaming bolus +14 ranged touch (7d6 fire)
Space 15 ft.; Reach 15 ft. (20 ft. with bites)
Special Attacks black smoke, flaming bolus
Abilities
Str 28, Dex 15, Con 22, Int 9, Wis 17, Cha 12
Base Atk +14; CMB +24 (+26 bull’s rush); CMD 36 (38 against bull’s rush)
Feats Blind-Fight, Combat Reflexes, Improved Bull’s Rush, Improved Critical (greataxe), Improved Initiative, Power Attack, Vital Strike
Skills Climb +17, Intimidate +14, Perception +20, Stealth +8, Survival +15; Racial Modifiers +4 Perception, +4 Survival
Languages Giant
Ecology
Environment temperate hills
Organization solitary, pair or gang (1-2 plus 3-6 hill giants)
Treasure double standard (greataxe, hide armor, other treasure)
Special Abilities
Black Smoke (Su) As a standard action, a cacus can expel a cloud of choking smoke in a 30 foot radius. The smoke blocks all sight within its depths, and any creature in the smoke must succeed a DC 23 Fortitude save or be staggered for as long as it remains in the cloud and for 1d4 rounds thereafter. This smoke lasts 1 minute, but can be dispersed by severe or stronger winds. The save DC is Constitution-based.
Flaming Bolus (Su) A cacus may vomit a ball of flaming sputum as a standard action. This is a ranged touch attack with a range of 120 feet and no range increment. A creature struck by the bolus takes 7d6 points of fire damage, and any creature adjacent to the target must succeed a DC 23 Reflex save or take the same amount of damage. A successful save halves the damage. A cacus can use this ability once every 1d4 rounds. The save DC is Constitution-based.
Poison (Ex) Injury—bite; save Fort DC 23; effect 1d3 Str; duration 6 rounds; cure 2 saves. The save DC is Constitution based.