Assassination Classroom. Volume 20: Yusei Matsui

What does a pathetic class of misfits have in their arsenal to combat their schoolteacher's alien technology, bizarre powers and...tentacles?!

The battle for Koro Sensei's life against a multinational operation's soldiers and weaponry is difficult enough, but now his creator and former protege, mad scientist Yanagisawa and Grim Reaper II, join the battle to destroy him-and they've both had major enhancements! But the stakes abruptly change when a 3-E student is fatally caught in the crossfire… If there's one thing that enrages 3-E's teacher, it's harming-let alone killing-his students! Koro Sensei's fury and ingenuity know no bounds, even as fate inexorably catches up to him…

The surprise-hit bizarre action comedy about a tentacled teacher with a heart that is a consistent Bookscan best seller.