The Dagger 'Dethanc' (2d4) (+9,+12) [+10]
Branded with lightning. Provides resistance to lightning. Cannot be harmed by acid, electricity, fire, cold.
When aimed, it creates a lightning bolt (that always beams) with damage 6d 6. Takes 7 to 12 turns to recharge.
Min Level 1, Max Level 50, Generation chance 40, 1.2 lbs

(Angband 3.1.2v2)