Ansatsu Kyoushitsu (Assassination Classroom) (2015) - 6/10
Film adaptation of Yuusei Matsui's cult comic, which revolves around a group of high school losers, who're being taught in classical subjects and trained as assassins at a traditional classroom in the middle of a forest by what they call 'Unkillable Teacher', an alien in form of a yellow octopus in a school professor's gown. The target of their assassination? The unkillable teacher himself.
While Unkillable Teacher teaches them to learn loving classical subjects and improving their killing techniques, they come to regard him as their greatest teacher for believing in them when no one else did. This becomes a dilemma because they know that if they failed to kill him before their graduation day, Unkillable Teacher will destroy their world that day.
Yes, it's as daft as it sounds. A fun popcorn film with a couple of laugh-out-loud moments. That's all you need to know, really.
Edited: Trailer -
https://www.youtube.com/watch?v=ra9IwKLiQXA