Elon Musk tweeted that Tesla's self-driving cars would cost more after July The Tesla and SpaceX owner, who topped the list of the world's richest persons last month, finally gave up when pestered by netizens as to how he was running several companies at the same time switching his focus from one to the other. In desperation, Musk replied to Tech start-up mogul Kunal Shah: "I'm an alien," perhaps as a last-ditch effort to end the discussion but it has bounced back with trolls and more questions on Twitter. Elon Musk Twitter HackIBT The bizarre Twitter exchange started when netizens questioned how he runs so many massive companies simultaneously. At the age of 49, running two huge companies -- the SpaceX and Tesla, Elon Musk is not only the richest person in the world but also the one steering the future of the humanity with his future space missions aimed at colonizing Mars.