It's the same mechanism as a short squeeze, just with the roles of stock and cash swapped. There is likely a specific word for that, but the comparison works.

Squeezed short sellers have an obligation to get a specific stock, but only have cash. There are not enough market participants willing to sell the stock, so the price rises astronomically to their disadvantage.

Elon has an obligation to get cash, but only has $TSLA stock. There are not enough market participants willing to buy the stock, so the price drops enormously to his disadvantage.