6. Return Of The Brain Spawn
Finally completing the Infosphere, the Brain Spawn make an unexpected and terrifying return. Surely such a super smart and formidable foe was bound to return eventually, stronger than ever and hell bent on havoc. However, this time they opt not to destroy the universe. In an act of sheer sadism, they just leave everybody stupid, except Fry of course, who is immune, so he ends up all alone in a cosmos entirely populated by dribbling idiots. By default, Fry is now the most intelligent human being in all eternity. We can only hope he has enough Slurm to keep him company, because the future is going to be an awfully bleak and lonely one.