If you're building or auditing anything that handles collateral, this day matters more than most UST had $18 billion in circulation at its peak. It died not because a smart contract had a bug, but because the reserve backing it was entirely circular: UST was backed by LUNA, and LUNA derived its value largely from UST's demand. There was no independent, automated, on-chain mechanism continuously verifying that the collateral was genuinely worth what the protocol assumed it was worth. When the...