The Zweihander 'Mormegil' (3d6) (-15,-15) [-10]
Heavily cursed. -10 speed. Slays undead. *Slays* dragons. Branded with venom. Cannot be harmed by acid, electricity, fire, cold. Sustains your life force. Grants the ability to see invisible things. Aggravates creatures nearby. Drains experience.
Min Level 30, Max Level 100, Generation chance 7, 25.0 lbs

(Angband 3.1.2v2)