"Tree Trunks" is the fourth episode of the first season of the American animated television series Adventure Time. The episode was written and storyboarded by Bert Youn and Sean Jimenez, from a story by Merriwether Williams and Tim McKeon. It originally aired on Cartoon Network on Monday, April 12, 2010. The episode guest stars Polly Lou Livingston as the titular Tree Trunks. 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, Tree Trunks joins Finn and Jake who go on a quest to fulfill her desire of picking a proposed legendary "crystal gem apple" in an evil forest. The three eventually find the tree, and Tree Trunks eats the apple, only to apparently explode and be transported to a crystal dimension. Tree Trunks was voiced by Polly Lou Livingston, a friend of series creator Pendleton Ward's mother. Ward asked Livingston to appear on his show several years after he last saw her. The original ending called for Tree Trunks to simply explode, but a new ending was amended to explain what happened to her. This served as the genesis for the second season episode "Crystals Have Power". The episode was viewed by 1.847 million viewers and received a 1.2 rating among adults between the ages of 18 and 49. The episode received largely positive reviews from critics, with many commenting on the episode's ending. Plot Finn and Jake are invited to the elephant Tree Trunks' house for apple pie. The group begins talking about what they wish they could do if they could achieve anything, and Tree Trunks notes that she wants to pick the rare Crystal Gem Apple, which is located in the Evil Forest. Finn and Jake decide to make her wish come true. When they reach the Evil Forest, they encounter a wall of flesh and try to fight it, but because Tree Trunks is naive, she begins putting stickers on it. After defeating the monster, Tree Trunks walks away, following a skeleton butterfly. She is attacked by sign zombies and begins having a tea party with them, not knowing they want to kill her. Finn and Jake fight off the Sign Zombies and continue their adventure, until they encounter a brain beast.