A critical vulnerability in an AI agent framework was weaponised within 20 hours this month. No proof-of-concept existed. Attackers built working exploits from the advisory description alone and began harvesting credentials at scale. This is the new reality: autonomous AI systems are being compromised faster than any governance framework can respond. The cybersecurity playbook built for static software doesn't work for agents that reason and act independently. This article introduces a biological alternative — governance modelled on immune system architecture that detects anomalies, contains damage without shutting down the enterprise, and learns from every encounter.