Bears are bulls supported by certain fundamentals, thinking that bears are unable to deliver when the contract expires, so they support the price. As long as the bears really can't deliver the goods, they can only lighten their positions and stop losses in futures, and then the bulls can make huge profits.

It must be a plunge after the failure of forcing the air. For example, the price of methanol at 14 and 12 is a typical plunge caused by the failure of forced opening, and the transaction can only be completed after three consecutive daily limit and market closure.