"Ricardio the Heart Guy" is the seventh 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, Tim McKeon, and Adam Muto. It originally aired on Cartoon Network on April 26, 2010. The episode guest stars George Takei (pictured) as the titular character, Ricardio. 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 believes that Princess Bubblegum's (voiced by Hynden Walch) new friend, a heart named Ricardio, is evil, and is proven right after learning that Ricardio is the heart of the Ice King (voiced by Tom Kenny). Ricardio reveals that he wants to "make out" with Bubblegum's heart, but he is defeated by Finn and Jake. Ricardio would become a minor recurring villain, reappearing in the fourth season entry "Lady & Peebles". After the episode aired, series composed Casey James Basichis posted a video explaining his inspiration and the method in which he produced the music featured in the episode. Basichis largely scored the episode with opera music, because he felt the genre suited Ricardio. "Ricardio the Heart Guy" was watched by 1.91 million people and received largely positive critical attention, with many reviews praising Takei's voice work.