Horned Beast (CR 4)

Medium Magical Beast
Alignment: Usually neutral evil
Initiative: +6 (+2 Dex, +4 Improved Initiative); Senses: darkvision 60 ft., low-light vision, Listen +7, and Spot +3

AC: 17 (+2 Dex, +5 natural), touch 12, flat-footed 15
Hit Dice: 4d10+12 (34 hp)
Fort +7, Ref +6, Will +2
Speed: 40 ft.
Space: 5 ft./5 ft.
Base Attack +4; Grapple +8
Attack: Gore +9 melee
Full Attack: Gore +9 melee (1d6+4) and bite +8 melee (1 plus poison); or bite +8 melee (1d4+4) and bite +8 (1d4+4
Special Attacks/Actions: Breath weapon, poison, superior weapon fighting
Abilities: Str 18, Dex 15, Con 17, Int 2, Wis 12, Cha 7
Special Qualities: light sensitivity, resistance to fire 10
Feats: Improved Initiative; Powerful Charge; Weapon Focus (gore)
Skills: Jump +8, Listen +7, Move Silently +5, Search -2, and Spot +3
Advancement: 5-8 HD (Medium); 9-12 HD (large)
Climate/Terrain: Temperate and warm hills and mountains
Organization: Solitary, pair, or pack (5-14)
Treasure/Possessions: None

Source: Tome of Magic

Breath Weapon (Su): 20-foot cone, once every 1d4 rounds, damage 3d6 fire damage, Reflex DC 15 half. The save DC is Constitution-based.

Poison (Ex): The horned beast's snake head delivers poison with its bite attack. Injury, Fortitude DC 15, initial and secondary damage 1d8 Dex. The save DC is Constitution-based.

Superior Natural Weapon Fighting (Ex): A horned beast bites opponents with both its goat head and its snake tail. Because each of its two heads controls a bite attack, both bites are considered primary natural attacks, and neither is subject to a penalty on attack or damage rolls as a secondary attack.

Light Sensitivity (Ex): A horned beast is dazzled while in bright sunlight or within the radius of a daylight spell.

Skills: Because of its two heads, a horned beast gains a +2 racial bonus on listen, Search and Spot checks.

A horned beast charges into combat to ram its foe. Then it lashes out with its bite attacks, often biting different creatures with each attack and then switching who gets bitten by which head. Whenever possible, it employs its powerful charge against its enemies, sometimes even retreating briefly from the fray so that it can come charging back.