Aave, a major DeFi lending protocol, suffered a $6 billion drop in Total Value Locked (TVL) following the "Kelp Hack." This incident exposed a critical structural risk in its design, where a flaw in a specific staking derivative (stETH) integration allowed an attacker to manipulate collateral and drain funds. The event highlights the systemic vulnerabilities in complex, interconnected DeFi systems and the importance of rigorous security audits for novel financial instruments.