Billionaire Elon Musk chose to dedicate a portion of his Sunday to mocking Bernie Sanders on Twitter. The world’s richest person and Tesla CEO stirred up online vitriol when he responded to a tweet from the senator that demanded “the extremely wealthy pay their fair share. Period.” Musk, whose net worth hovers roughly around $271 billion, wrote: “I keep forgetting that you’re still alive.” Seemingly unsatisfied leaving it at that, he then added, “Want me to sell more stock, Bernie? Just say the word....”

Musk and Sanders have sparred previously, with Sanders telling Musk in March to “focus on Earth” instead of aiming his vast wealth at interplanetary travel. Sanders has also tweeted out that Musk’s “level of greed and inequality” is “immoral” and “unsustainable.” The billionaire’s taunts come after he dumped nearly $7 billion worth of shares in Tesla this week, following a Twitter poll he hosted asking his followers if they thought he should sell.