暗殺教室 [Ansatsu Kyōshitsu / Assassination Classroom]

A bizarre, yellow, tentacled creature—who claims to have already destroyed the moon and plans to do the same to Earth—takes over a classroom of misfit students at Kunugigaoka Junior High, tasking them with one impossible assignment: assassinate him before graduation. Running in 集英社's Weekly Shōnen Jump from 2012 to 2016, this 21-volume series from creator Yūsei Matsui blends dark comedy, heartfelt mentorship, and relentless action. Its central question—what does it mean to teach and learn from a target you must kill—made it a defining shōnen hit of the 2010s.