Yu-Gi-Oh! GX Episode 167: Gratitude Duel! Chronos VS The Original Dropout Boy
Episode 167 of 180 of Yu-Gi-Oh! GX, aired December 26, 2007, 25 minutes. Available with English subtitles and dub where released.
Episode summary
When Crowler looks at the Graduation Album, he begins to act abnormal. He conducts rigid classes for no reason, suddenly make his students dictate multiplication tables and make them do push-ups... in the end, they end up boycotting the lessons and fleeing. Jaden then challenges Crowler to a duel, the first since the entrance exams.