What's the sickest villain introduction of all time?

When a villain comes onto the scene for the first time in a movie, book or TV show, he or she has to do something to make a mark right away. Put an eel in someone's ear. Murder someone we love. Do something horrible. What's the darkest, most memorable villain introduction ever?

Please include a clip or picture of this totally insane scene. And please mention where it comes from, and why it establishes the villain right away.