Well, you sort of violated the "or painfully" bit...
Anyway. Your English teacher becomes smarter. So much smarter, in fact, that he realizes how much potential he really has. He immediately invests his life savings in AIG (EVERYONE DO THIS, IT IS TOTALLY FINANCIALLY ADVISABLE) and makes millions. You are left with a substitute teacher so idiotic, he can barely manage to move and keep from pooping his pants at the same time. However, he still accidentally gives the whole class detention for three years, enforced by armed guards (he somehow lists you all as murderer-rapists). Your former teacher runs off to Harvard, enrolls in every class, builds a robot to synthesize the information and deliver it to his brain, and leaps forward mentally. He uses his learning in his computer classes to hack into the Harvard database and steal lesson plans and Powerpoints, skimming the information and extrapolating. He soon learns everything Harvard has to offer, and does the same with every major university on the planet. By now he has upgraded his huge cyborg brain to be housed in a several-story building protected by massive armies of diverse robots (internet-incapable robots that thus cannot be attacked with a virus, EMP-hardened robots, etc) and other defenses. He has only one shred of humanity left: Hatred. Hatred for you pathetic fools who failed his class. Hatred for you class clowns, you troublemakers, you idiots. He uproots his entire city-sized base and marches over, encasing you all in cryogenic freezing compartments. He develops near-immortality. His hatred for you in particular is unbounded, and so he gives you a pill that lets you regenerate very quickly, in just a few hours. For endless eons he tortures you, your screams of agony echoing in the wastelands of what was once called Earth. No man lives to listen to your pain. You are his mere plaything, reduced to a life of no hope, only hurt.
I wish my computer was faster (Don't do running faster, that's lame).