Last month, the director of the United Nations’ World Food Programme called on the world’s richest man to help solve the global hunger crisis. Taking to Twitter, David Beasley challenged Elon Musk to donate some of his wealth to the cause.

“Congratulations to @elonmusk for passing up @JeffBezos as the world’s richest person,” Beasley wrote. “Elon, to celebrate I’m offering you a once in a lifetime opportunity: help us save 42M people from starvation for just $6.6B!! Offer expires SOON.. and lives do too.”