A developer built NOCK, a risk detection system for DeFi protocols, during the Nansen Meridian Buildathon. NOCK monitors vaults and lending markets across multiple blockchains to detect unusual capital outflows and collateral contagion, alerting users and enabling automated fund recovery. The tool demonstrated effectiveness in identifying risks from major 2026 exploits including Drift, Kelp's bridge drain, and Bitget's wallet breach.