Yu-Gi-Oh! 5D's - Season 1 Episode 67 : Lessons Learned 2011

As Yusei and Crow work on their new engine, they are visited by Leo, Luna and their classmates, including the timid Sly, who is nearly tempted to steal Stardust Dragon. Yusei is asked by the Academy's principal to fix something, which turns out to be the head instructor, Rudolph Heitmann, who is threatening to expel Leo, Luna, and their friends for using low level monsters. Yusei arrives, and challenges Heitmann to a duel, in order to stop them getting expelled, and to prove the strength of low level monsters. Heitmann manages to summon three Ancient Gear Golems on his first turn and deals a lot of damage. Yusei summons out Stardust Dragon, but sacrifices him to summon out several Tuner monsters, which belong to the relevant students. Yusei manages to use them to defeat Heitmann, who learns his lesson, and withdraws the expulsions. As Yusei leaves, Sly contemplates to steal Stardust Dragon. Fortunately, he will never get that chance.