Fulminator

Fulminator is a Legendary sword in Diablo III, one of the five Quinblades. It requires character level 31 to drop.

It's unique property causes enemies to crackle with lightning bolts, hitting all other enemies within a ~10 yard radius of the target on which it triggered. Affected targets do not take damage from the effect themselves.

Because the elements of your chosen skills override any elemental damage properties on weapons, Fulminator's unique property will only function when using skills that deal Lightning damage. It's inherent Lightning damage cannot trigger the property when using skills of a different element.