lightning rod

noun

a rodlike conductor installed to divert lightning away from a structure by providing a direct path to the ground.
a person or thing that attracts and absorbs powerful and especially negative or hostile feelings, opinions, etc., thereby diverting such feelings from other targets: The unpopular supervisor served as a lightning rod for the criticism that should have been aimed at management.

Origin of lightning rod

An Americanism dating back to 1780–90

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Buying this ticket is like buying a lightning-rod; it may draw off the lightning!
The Trimming of Goosie
James Hopper
When it was nearing completion, the question arose, should they put on a lightning-rod.
Preventable Diseases
Woods Hutchinson
You never need a lightning-rod, because it never thunders and it never lightens.
Roughing It
Mark Twain (Samuel Clemens)
And if the house was struck by lightning, he went out and put up a lightning-rod.
Stories of Invention
Edward E. Hale
It is even said that he made here his first experiment with a lightning-rod.
Friends of France
Various

lightning rod in Science

A grounded metal rod placed high on a structure to conduct electrical current from a lightning strike directly to the ground, preventing the currents from injuring people or animals or from damaging objects. Lightning rods usually have a sharp, pointed tip, since electric lines of force are more highly concentrated around pointed objects, in this case increasing the attractiveness of the rod compared with other nearby objects. See also Saint Elmo's fire.