Ansatsu Kyoushitsu

Synopsis

With the end-of-term final exams approaching, Koro-sensei offers an incentive in which each student who gets the best overall score in their top subject will get to shoot off one of his tentacles. Meanwhile, Shindo informs Class 3-E about Class 3-A's "Big Five," led by Asano's son Gakushu, who are determined to take 3-E down. When some of the 3-E students go to study in the main campus library, the Big Five propose a contest in which whichever class snags the most top spots in the exams can demand anything from the losing class. Class 3-A sets their sights on making 3-E show complete servitude to them, with Gakushu hoping to find out the class' secret, while Koro-sensei proposes his own suggestion of what 3-E can ask from their opponents. With both classes determined to win, the stage for the end-of-term finals is set.

(Source: Wikipedia)