Elder Serpent Huge Viper* (CR 5)

Huge Magical Beast (Augmented Animal)
Alignment: Neutral evil
Initiative: +7 (+3 Dex, +4 Improved Initiative); Senses: blindsense 70 ft., scent, Listen +18, and Spot +18

AC: 17 (-2 size, +3 Dex, +6 natural), touch 11, flat-footed 14
Hit Dice: 8d10+16 (60 hp)
Fort +8, Ref +9, Will +7
Speed: 20 ft., climb 20 ft., swim 20 ft.
Space: 15 ft./10 ft.
Base Attack +8; Grapple +20
Attack: Bite +11 melee
Full Attack: Bite +11 melee
Damage: Bite 1d6+6 plus virulent poison
Special Attacks/Actions: Command serpents 4/day, mesmerizing sway, virulent poison
Abilities: Str 18, Dex 17, Con 15, Int 13, Wis 21, Cha 11
Special Qualities: speak with serpents (huge viper base creature)
Feats: Improved Initiative; Run; Weapon Focus (bite)
Skills: Balance +11, Bluff +4, Climb +12, Hide +4, Intimidate +4, Listen +18, Search +5, Sense Motive +9, Spot +18, and Swim +12
Advancement: By character class
Climate/Terrain: Temperate hills (Serpent Hills)
Organization: Solitary
Treasure/Possessions: Standard

Source: Dragon #313

An elder serpent viper nearly always begins a battle with its mesmerizing sway ability. Once opponents are under its influence, it resorts to melee attacks, trying to bite several opponents in succession to spread its virulent poison among as many targets as it can. An intelligent combatant, this creature does not hesitate to flee a fight that goes poorly, waiting for its poison to take full effect before returning to resume the battle.

The Will save DCs against the elder serpent Huge viper's mesmerizing sway and command serpents powers are each 14. The DCs are Charisma-based. The Fortitude save DC against its virulent poison is 18, and the poison's initial and secondary damage ratings are each 1d6 Str and 1d6 Con. This DC is Constitution-based.

Augmented Subtype

A creature receives this subtype whenever something happens to change its original type. Some creatures (those with an inherited template) are born with this subtype; others acquire it when they take on an acquired template. The augmented subtype is always paired with the creature's original type. For example, a wizard's raven familiar is a magical beast (augmented animal). A creature with the augmented subtype usually has the traits of its current type, but the features of its original type. For example, a wizard's raven familiar has an animal's features and the traits of a magical beast.