Adventure Time Season 10 Episode 5 - Seventeen Episode Title:Seventeen.Episode Description:At Finn's seventeenth birthday party (held at the Candy Kingdom), Princess Bubblegum, Marceline, Huntress Wizard and BMO give him gifts. The Green Knight (voiced by Brad Neely) arrives, and gives Finn an ax he can keep if he attacks him with it. Thinking that it is one of Jake's tricks, Finn beheads the Green Knight; Jake arrives, and the Knight challenges him to a battle by blocking him from his friends. Finn accepts, and they play the party games two-on-three. While they are arm-wrestling, the Knight reveals himself as a revived Fern and defeats Finn. He is stopped by Gumbald, who reveals that he, Lolly and Chicle were restored from being exposed to Lumpy Space Princess' transformation of Ooo at the end of Elements. The trio and Fern leave, and Finn is devastated by his loss.