Steady Weapon
This ability is usually placed on long spears. More rarely, a sarissa (pike) or other weapon that can use the brace action will be so enchanted. They are designed to hold charging beasts (or cavalry) at bay, and have a reinforced shaft.

A steady weapon has an additional +1 to attack against a charging foe, when braced, and gives its wielder the ability to make an attack of opportunity against a charging opponent who enters an area it threatens. This attack of opportunity happens immediately before the charge attack is resolved. Steady weapons save against breakage due to impacts at +6.

Aura moderate divination; CL 5th; Craft Magic Arms and Armor, mending, true strike; Price +5,000 gp.