When the Frax protocol is attacked by a short seller, a "Bank Run" will occur, resulting in a death spiral. The details are as follows: short sellers short the stablecoin FRAX and the governance token FXS, the price of FRAX drops below $1, users redeem FRAX in large quantities to get USDC and FXS, and users sell FXS, which causes the price of FXS to continue to fall. Although when FRAX price falls below $1, the system collateral ratio will increase, but since no user is willing to deposit USDC into the system at this time, the sooner users who redeem FRAX will get more USDC, and the later users who redeem FRAX will get less USDC. The users will rush to redeem FRAX and sell FXS, and the system will fall into a death spiral.