"The Enchiridion!" is the fifth episode of the first season of the American animated television series Adventure Time. The episode was outlined, written, and storyboarded by Patrick McHale, Adam Muto, and Pendleton Ward. It originally aired on Cartoon Network on April 19, 2010. The episode guest stars Henry Rollins, John Moschitta Jr., and Mark Hamill. The series follows the adventures of Finn (voiced by Jeremy Shada), a human boy, and his best friend and adoptive brother Jake (voiced by John DiMaggio), a dog with magical powers to change shape and grow and shrink at will. In this episode, Finn and Jake go on a quest for the titular magical book that would prove them worthy of being righteous heroes. After passing through a series of trials and tribulations, Finn acquires the legendary book. The first episode produced for the series, "The Enchiridion!" was crafted to retain the same spirit as the earlier series' pilot. The middle section originally featured several more trials, but many of them were cut for time. The episode was viewed by 2.096 million viewers, and received generally positive remarks from critics, although several noted that it was noticeably different from the remainder of the series, due to the show's eventual evolution. The episode was later adapted as part of a Level Pack for the 2015 video game Lego Dimensions. Plot After a party that results in Finn saving Princess Bubblegum from falling from her tower, she decides that he is worthy of reading the Enchiridion: a tome of heroic knowledge. The book can only be acquired by "for heroes whose hearts are righteous". Bubblegum reveals that the book is located at the top of Mount Cragdor, past several trials. After passing the doorkeeper (voiced by John Moschitta Jr.), Finn and Jake encounter gnomes who cause Finn to doubt himself. When Jake tries to cheer him up, he is eaten by an ogre. Believing his friend to be dead, Finn steals a giant dollar from the ogre and attacks him, hitting him in the groin. The Ogre vomits Jake up, and the two glide to the end of the trials. Finn, however, makes sure to send the dollar back to the Ogre, causing Jake to call his act "righteous". Once inside the top-most building of Mount Cragdor, a malevolent entity (voiced by Mark Hamill) takes Finn to his "Brain World", wherein he is first told to slay