"King Worm" is the eighteenth episode of the fourth season of the American animated television series Adventure Time. The episode was written and storyboarded by Steve Wolfhard, Somvilay Xayaphone, and Bert Youn, from a story by Patrick McHale, Kent Osborne, and Pendleton Ward. It originally aired on Cartoon Network on August 13, 2012. The episode guest stars Erik Estrada as the titular King Worm.