Sayonara, Zetsubou-Sensei

This episode is a pastiche of parodies about foreigners and Japanese attitudes concerning them. A foreign student named Kaere Kimura transfers into the class. Nozomu initially hopes to use her to bring up the class average; his attitude subsequently shifts to horror at the thought of an obnoxious 'returnee' that corrects his English, then fear that she will sue him for sexual harassment. Kimura is a blonde girl with multiple personality disorder stemming from cultural identity confusion (Kaere: the foreign personality; Kaede: the Japanese one). After an incident on the school rooftop, Kaere threatens Nozomu with a lawsuit, after which he disappears; while taking roll, Ms. Arai uncovers an illegal immigrant who purchased the name and seat of "Tarou Sekiutsu" from their original owner. (Source: Wikipedia)