The old saying "if it ain't broke, don't fix it" often comes to mind when brands decide to change iconic formulas or familiar packaging. In fact, when companies decide to make a bold product change, it can backfire spectacularly.

From the cereal rebrand that went horribly wrong to the Pizza Shapes recipe change that led 30,000 people to sign a petition in protest, read on to discover 18 product changes and rebrands that flopped.

All dollar amounts in US dollars.