Dictionary
light'ning rod"
1. a rodlike conductor installed to divert lightning away from a structure by providing a direct path to the ground.
2. a person or thing that attracts and absorbs powerful and esp. 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. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.