McDonald’s has announced that it’s tweaking its burgers to enhance their flavor and overall appeal. Judging from history, the move will either prove a stroke of genius or one of the worst mistakes Big Mac has ever made.

This week on Restaurant Rewind, we look back at what happened when Big Mac’s chief rival overhauled its main customer lure. Join me as we recount how Burger King’s revamped Whopper was received. (Here’s a hint: You won’t find the updated version on the menu today.)