GlassWorm is the first known self-propagating worm targeting developer environments by infecting VS Code extensions with hidden Unicode payloads. Once installed, it steals credentials from NPM, GitHub and Git, and upgrades machines into proxy nodes and part of a distributed criminal infrastructure. It uses a blockchain-based command and control mechanism and auto-updates to spread across the developer ecosystem. In this article, we dissect how GlassWorm works, what makes it a paradigm shift in supply-chain attacks, and what organisations must do to detect and contain it before their dev workstations become weaponised.