While you might think that SpaceX and Tesla are more than enough to keep Musk on his toes, he's got other plans up his sleeve. "We have planes, trains, automobiles and boats... What if there was a fifth mode?" Musk famously mused in July 2012, before unveiling plans for his "Hyperloop" transportation system the following year.
The visionary new approach to getting from A-to-B would see pods sent hurtling through a vacuumed tube at lightning speeds – for example, the four-hour journey between LA and San Francisco would be slashed to around 30 minutes.
Key to the plan is a network of tunnels and, with this in mind, Musk set up a firm dedicated to boring holes in the ground. The Boring Company (get it?) was founded in 2016 and set to work tunnelling under the Las Vegas Convention Center.
So far, the Hyperloop project has had very limited success – perhaps because Musk and his engineers have been entertaining themselves with dangerous gadgets instead.
In January 2018, The Boring Company developed its controversial "flamethrower". Comprising a blowtorch shaped like a gun, 20,000 of them were made available for pre-order. Perhaps unsurprisingly, they'd all sold out by the end of the month.