SRD:Hammer of Thunderbolts
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Hammer of Thunderbolts: This +3 Large returning warhammer deals 4d6 points of damage on any hit. Further, if the wielder wears a belt of giant Strength and gauntlets of ogre power and he knows that the hammer is a hammer of thunderbolts (not just a +3 warhammer), the weapon can be used to full effect: It gains a total +5 enhancement bonus, allows all belt and gauntlet bonuses to stack (only when using this weapon), and strikes dead any giant upon whom it scores a hit (Fortitude DC 20 negates the death effect but not the damage).
When hurled, on a successful attack the hammer emits a great noise, like a clap of thunder, causing all creatures within 90 feet to be stunned for 1 round (Fortitude DC 15 negates). The hammer’s range increment is 30 feet.
Strong evocation, necromancy, and transmutation; CL 20th; Weight 15 lb.