SRD:Soulbreaker

Soulbreaker: This weapon has a special ability that functions only upon scoring a successful critical hit. On a successful critical hit, a soulbreaker weapon bestows one negative level on the foe. One day after being struck, if the negative levels have not been purged, the subject must succeed on a DC 18 Fortitude save for each negative level or lose a character level.

Strong telepathy; ML 12th; Craft Psionic Arms and Armor, mindwipe; Price +3 bonus.