Random Magic Weapons (any level)

A brilliant energy weapon has its significant portion - such as its blade, axe head, or arrowhead - transformed into light, although this does not modify the item's weight. It gives off light as a torch (20-foot radius). A brilliant energy weapon ignores nonliving matter. Armor and enhancement AC bonuses do not count against it because the weapon passes through armor. (Dexterity, deflection, dodge, natural armor, and other such bonuses still apply.) A brilliant energy weapon cannot harm undead, constructs, and objects. Bows, crossbows, and slings cannot be enchanted with this ability.
Caster Level: 16th
Requirements: Craft Magic Arms and Armor, gaseous form, continual flame
Price: +4 bonus
Source: Dungeon Master's Guide v.3.5