Random Magic Weapons (any level)

A thundering weapon creates a cacophonous roar like thunder upon striking a successful critical hit. The sonic energy does not harm the wielder of the weapon. Thundering weapons deal +1d8 points of bonus sonic damage on a successful critical hit. If the weapon's critical multiplier is x3, add +2d8 points of bonus sonic damage instead, and if the multiplier is x4, add +3d8 points of bonus sonic damage. Bows, crossbows, and slings so enchanted bestow the sonic energy upon their ammunition. Subjects dealt a critical hit by a thundering weapon must make a Fortitude save (DC 14) or be deafened permanently.
Aura: Faint necromancy
Caster Level: 5th
Requirements: Craft Magic Arms and Armor, blindness/deafness
Price: +2 bonus
Source: Dungeon Master's Guide v.3.5