SRD:Souldrinker

Souldrinker
This +5 bastard sword bestows 2d4 negative levels on its target whenever it deals damage, just as if its target had been struck by the energy drain spell. Each negative level bestowed grants the wielder 5 temporary hit points. One day after being struck, the subject must make a Fortitude save (DC 25) for each negative level or lose a level. If this sword’s power causes a character to have negative levels at least equal to his or her current level, the character is instantly slain and the wielder gains an additional 10 temporary hit points. Temporary hit points gained from this weapon last for a maximum of 1 hour.

Caster Level: 21st; Prerequisites: Craft Magic Arms and Armor, Craft Epic Magic Arms and Armor, Spell Focus (Necromancy), energy drain; Market Price: 478,335 gp; Cost to Create: 239,315 gp + 14,780 XP.