No matter how much you try to believe in basic human goodness, there are those who will prove the other way. These people have done the most atrocious crimes one could ever imagine. They have already sealed their name as among the worst serial killers ever. They have different underlying reasons for their actions. Some did it as a form of revenge while others did it just for fun. Be warned though. You might not stomach what they have done to their victims as discussed in this list.