Tesla$Tesla Motors(TSLA)$ stock is one of the most popular and widely traded shares in the US, UK and elsewhere. But investing in Elon Musk’s electric-vehicle maker is like riding the world’s roughest roller coaster. Indeed, Tesla investors need strong stomachs to ride out this stock’s crazy volatility.Tesla stock soars and roarsSince late 2019, Tesla stock has been on a massive, explosive upward surge. At the end of 2019, the shares closed at $83.67. But during the Covid-19 crisis of 2020-21, Tesla became a leading meme stock — and buying pressure caused by millions of fans sent its shares skyward like a SpaceX rocket.On 31 December 2020, Tesla stock broke $700 for the first time, hitting an intra-day high of $718.72 before ending the year at $705.6