"Mortal Folly" and "Mortal Recoil" are the twenty-fourth and twenty-fifth episodes of the second season of the American animated television series Adventure Time. "Mortal Folly" was written and storyboarded by Adam Muto and Rebecca Sugar, whereas "Mortal Recoil" was written and storyboarded by Jesse Moynihan and Cole Sanchez. Both were based on a story by Mark Banker, Kent Osborne, Patrick McHale, and series creator Pendleton Ward. The two episodes originally aired on Cartoon Network on May 2, 2011, and guest starred Ron Perlman as the Lich, and Isabella Acres as young Princess Bubblegum. Perlman's character would become the series' chief antagonist, and would reappear in several fourth and fifth season episodes.