A DeFi user experienced a significant financial loss on March 12 after attempting a swap transaction involving $50,432,688, ultimately receiving only $36,000 due to a 99.9% price impact. The incident, involving Aave and CoW Swap, highlights the critical importance of understanding price impact versus slippage in decentralized finance transactions. Price impact occurs when a large order affects the market price due to low liquidity, unlike slippage, which is caused by market volatility. The transaction interface had warned the user of the potential for a 100% value loss, but the user proceeded after acknowledging the risk. This event underscores the need for DeFi users to carefully evaluate transaction quotes and consider alternative strategies, such as splitting orders or using over-the-counter trading, to mitigate risks. In response, Aave has introduced the Aave Shield feature to block transactions with excessive price impacts, aiming to enhance user safety while maintaining the core principles of DeFi.