Kain Darkwind's Savage Tide
Thorhöggva is a +3 dwarvencraft warhammer of returning with a 30ft range increment.
On a melee critical hit, a bolt of lightning strikes the foe, dealing 3d6 electricity damage (Reflex DC 16 half; 3d10 in stormy area) On a thrown critical hit, the bolt of lightning is followed by a thunderclap (20 ft. radius centered on foe, 10d6 sonic, Fort DC 18 half).
When thrown, Thorhöggva can strike multiple foes with iterative attacks before returning.
In the hands of Einar Sigurdsson, the Reflex save against electricity is DC 23, and against thunder, DC 25.