Size/Type: Huge Animal
Hit Dice: 6d8+6 (33 hp)
Initiative: +6
Speed: 20 ft. (4 squares), climb 20 ft., swim 20 ft.
Armor Class: 15 (-2 size, +2 Dex, +5 natural), touch 10, flat-footed 15
Base Attack/Grapple: +4/+15
Attack: Bite +6 melee (1d6+4 plus poison)
Full Attack: Bite +6 melee (1d6+4 plus poison)
Space/Reach: 15 ft./10 ft.
Special Attacks: Poison
Special Qualities: Scent
Saves: Fort +6, Ref +7, Will +3
Abilities: Str 16, Dex 15, Con 13, Int 1, Wis 12, Cha 2
Skills: Balance +10, Climb +11, Hide +3, Listen +7, Spot +7, Swim +11
Feats: Improved Initiative, Run, Weapon Focus (Bite)
Environment: Temperate Marshes
Organization: Solitary
Challenge Rating: 3
Alignment: Any
Advancement: 7-18 (Huge)
Level Adjustment: —
These creatures range widely in size. They are not particularly aggressive, but will often lash out with a bite attack before attempting to retreat.
Combat
Viper snakes rely on their venomous bite to kill prey and defend themselves.
Poison (Ex): A viper snake has a poisonous bite that deals initial and secondary damage of 1d6 Con. The save DC varies by the snake’s size, with the Huge Viper's Save DC being 14. The save DCs are Constitution-based.
Source: Monster Manual 1