Magic Weapon Abilities - Viper

Upon command, a viper weapon transforms its blade or lash into a viper one size category smaller than the wielder for which it is sized. For example, the blade of a greatsword sized for a Large character temporarily becomes a Medium viper, while the blade of a dagger sized for a Small character temporarily becomes a Tiny viper.
The wielder of a viper weapon uses his own attack bonus or that of the viper, whichever is higher, when making an attack with the transformed weapon. The damage dealt is always equivalent to the base damage for the bite attack of the appropriate kind of viper, plus the weapon's enhancement bonus and any other applicable modifiers. A successful attack also delivers the viper's poison. When thus transformed, viper weapons are always treated as piercing weapons.
This ability can be applied up to three times to a scourge, with each application converting one lash into a viper. When a viper scourge is used with an attack action, only one viper can attack; when it is used with a full attack action, all three can attack.
Only bladed weapons (including daggers and swords), scourges, and whips can become viper weapons. (If this special ability is rolled randomly for an inappropriate weapon, reroll.) All weapons with this special ability are emerald-green in hue and covered in scales.
A typical bladed viper weapon is crafted with a ring-pommel that allows the bearer to hang it from a belt, tie it to his wrist for use in mounted combat, or lower it on a cord through trapdoors onto intruders below. (This last usage always employs the viper's attack bonus for attacks.)
Aura: Moderate conjuration
Caster Level: 6th
Requirements: Craft Magic Arms and Armor, summon monster I (Small or smaller weapons), summon monster II (Medium weapons), or summon monster III (Larger or larger weapons)
Price: +1 bonus
Serpent Kingdoms