VorpalEquipment 17
Source Pathfinder Core Rulebook
Price 15,000 gp
Weight negligible
Originally created as a means of slaying the legendary jabberwock, vorpal weapons prove equally effective against nearly any foe with a head.
Activate 
envision (death, incapacitation)
Frequency You roll a natural 20 on a Strike with the weapon, critically succeed, and deal slashing damage. The target must have a head
Effect The target must succeed at a DC 37 fortitude save or be decapitated. This kills any creature except ones that don't require a head to live. For creatures with multiple heads, this usually kills the creature only if you sever its last head.
Traits
This rarity indicates that a rules element is very difficult to find in the game world. A rare feat, spell, item or the like is available to players only if the GM decides to include it in the game, typically through discovery during play. Creatures with this trait are rare. They typically can't be summoned. The DC of Recall Knowledge checks related to these creatures is increased by 5.
EvocationEffects and magic items with this trait are associated with the evocation school of magic, typically involving energy and elemental forces.
MagicalSomething with the magical trait is imbued with magical energies not tied to a specific tradition of magic. A magical item radiates a magic aura infused with its dominant school of magic. Some items or effects are closely tied to a particular tradition of magic. In these cases, the item has the arcane, divine, occult, or primal trait instead of the magical trait. Any of these traits indicate that the item is magical.