Arthur's Underwear is the first part of the fifth episode of Arthur season 2. Arthur's Underwear aired on October 20, 1997. It aired with "Francine Frensky, Olympic Rider".
Arthur can't stop laughing after Binky accidentally rips his pants in class, but then, he is having nightmares where he does not have any pants. He tells Buster about this, who tells everyone else, which embarrasses him. Inevitably, Arthur does rip his pants and has to deal with the fact that everyone gets embarrassed.