Did you know that it was Duracell themselves who invented the Energizer Bunny?
Coppertopped battery manufacturer Duracell began using a pink bunny in their adverts in 1972. Famously one of those adverts featured a lineup of similar pink bunnies, with the logos of other rival firms, which of course ran out of power long before their own did. In that advert, the Energizer bunny was born. Furthermore, whilst Duracell had registered the bunny as a trademarked device, they neglected to renew this registration for North America in 1979.
Even still, it took another decade before the ad agency for Energizer decided to lampoon the Duracell ads with their own much cooler pink bunny in 1989 (he/she had sunglasses).
To this day, both firms public images are represented by almost identical pink bunny rabbits. So much for differentiating themselves in a dull market full of the same rival products.
Who knows, it may have also helped the sales of yet another battery powered rabbit too.