From Wikipedia, the free encyclopedia. Kate Boutilier is an American screenwriter who is best known for writing Klasky Csupo shows like Rugrats, The Wild Thornberrys and All Grown Up!. She now writes shows aimed for younger viewers like Olivia and The Mr. Men Show. She is currently working on a show for Nickelodeon UK called Poppy Cat. Description above from the Wikipedia article Kate Boutilier, licensed under CC-BY-SA, full list of contributors on Wikipedia