Complex sentence: When the Duracell Bunny debuted in North America, it was intended to be just a one-shot character, but when Energizer's parody became a great success, Duracell decided to revive the Duracell Bunny.
Split into simpler sentences: When the Duracell Bunny debuted in North America, it was intended to be just a one-shot character. But when Energizer's parody became a great success, Duracell decided to revive the Duracell Bunny.