Elon Musk's son makes high-profile visit to the Oval Office. His mom, Grimes, isn't pleased The Oval Office generally maintains a rather formal air. But when Elon Musk's 4-year-old son, X Æ A-Xii (known as X), waltzed in on Feb. 11, he made himself right at home.

It’s not draconian or radical,” the billionaire said in a lengthy question-and-answer session alongside President Trump that sought to make the case for his Department of Government Efficiency.