Now that's a good cursed sword

Found in Dragon 42

Tyrfing was forged (under duress with death-threats) by the dwarves Dulin and Davlin, for Svafrlami, the grandson of Odin. The hilt and handle of Tyrfing are made of gold. The sword will never
rust and cuts through iron as if it were cloth. The sword has been cursed by its dwarven makers. It must take a life each time it is unsheathed. With it, three infamous deeds will be performed. While the sword will normally bring victory, because of the curse, there is an 3% chance (per battle) that the sword will turn on its owner, never hitting, possibly falling from their hand.

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Claytonian at the gmails.