Complex sentence: The most successful parody artist is "Weird Al" Yankovic who is now in his fourth decade of creating song parodies and has sold more than 12 million albums (more than any comedy act in history).
Split into simpler sentences: The most successful parody artist in recent history is "Weird Al" Yankovic who is now in his fourth decade of creating song parodies. He has sold more than 12 million albums (more than any comedy act in history).