Jessica Alba has three arms

Jessica Alba shows off her rare third arm at the world premiere of her film Fantastic 4: Rise of the Silver Surfer on June 12, 2007. This was at the Vue West End theater in London, England on June 12, 2007. (Jessica Alba doesn't have three arms, of course. The third arm belongs to another person lurking behind her. But what a superpower a third arm would be! Essay prompt: Would you rather fight crime by being invisible, as her character Sue Storm is in this film, or by having a third arm?)