4. Trying To Murder Selma
In the 1992 episode, "Black Widower", and coming two years after Sideshow Bob first became a household name on the Simpsons, we see Bob in all his criminal mastermind glory. After using the prison's pen-pal system to charm Bart's aunt, Selma, the two strike up one of the show's craziest of relationships when they get hitched. Bart however suspects there is more to Bob's plans to simply marry his aunt, and is proven correct when it is revealed he was plotting to murder her and inherit the money she recently earned on the stock-market. After Bob leaks gas into Selma's hotel room, blowing it up and thinking he has gotten away with his plan, he is instead thwarted when, thanks to some MacGyver-esque detective skills, Bart was able to ingeniously foil his evil plot. One of the reasons why we loved Sideshow Bob in this particular episode was because the story actually built on Bob's character, transforming him from a predictable, one-track villain out to kill Bart into a criminal mastermind with more malevolent intentions.