If you had superpowers

[Dystopia]

If this counts, I'll chose something called a Death Note, those of you who've watched anime will know. Death Note is pretty much a book with infinite pages, you write down a person's first name and surname, think about her face as you write it down, and 40 seconds later the person dies of heart attack. Alternatively, you can write down the cause of death you wish the person to have to avoid suspicion.

I'd use it to rule the world