When I was a kid, I'm pretty sure I had a story where the mayor, or the mayor's wife (I forget who was who) was kidnapped and cloned. When poor Jeffrey Socialite went to rescue his wife, he found 7 identical Mariah Carey sims and then the mad scientist fellow who had done it.
In the Sims 2, I ran a psuedo-medieval neighborhood with mods, so that flu could kill sims, and only nuns could make Grandma's Comfort Soup, the cure for the flu. It was highly contagious, so it regularly ran through the neighborhood and destroyed family lines. I had SEVERAL cemeteries in that neigborhood. :D