Energizer Bunny

The Energizer Bunny is the official masctr of Energizer. It's a mechanical toy rabbit playing the brass drum with the Energizer logo, wearing sunglasses, while rocking blue flip-flops.

The Energizer Bunny originally was made to mock Duracell's pink bunny mascot, but when the ads aired. The consumers thought that the pink bunny meant that Duracell was advertising their batteries, while the ads aired. Because of the fact that the pink bunnies were associated with Duracell. So while Energizer aired the ads, they were loosing money while helping their competetor.

(Info from Wikipedia)