On his average days, the space czar, social-media baron and electric car kingpin known as Elon Musk tweaks algorithms, ponders the profit margins of the universe and, depending on your biases, plays the role of the archetypal bad guy in a James Bond film. But Musk, too, has a vision of villainy in this world, as he let the world know via Twitter this week. It looks like the 92-year-old Hungarian-born billionaire philanthropist known as George Soros. “Soros reminds me of Magneto,” Musk wrote on Twitter, referring to the Marvel Comics character described as a tortured Holocaust survivor with the...