Engrish The Animation.
What They Say:
One day a weird tentacle creature destroys 70% of the moon and threatens to do the same to Earth in a year. However in exchange for being allowed to teach a group of misfit students called the E-Class, he’ll allow them to try and assassinate him. With the chance to earn 10 billion yen and prove their worth to the world, the kids are willing to give it a shot, but this thing might just end up being the best teacher they’ve ever had.