What is an uptier (non-pro-rata 'liability management') transaction, and why is it called creditor-on-creditor violence?

An uptier is a liability-management exercise where a company, with the consent of a majority of lenders, issues new super-senior debt and lets the consenting majority exchange their existing loans into it — leapfrogging the non-participating minority, who are left structurally subordinated and often stripped of covenant protections via the same majority vote. It's called creditor-on-creditor violence because the value transfer is from one group of lenders to another (the favored majority) rather than the usual borrower-vs-lender tension — same-class creditors are pitted against each other. It exploits loose credit-agreement provisions (pro-rata sharing, sacred-rights, and amendment thresholds). Drop-down transactions (moving assets to unrestricted subsidiaries to raise new debt away from existing lenders, e.g., J.Crew) are a cousin. They've driven litigation and tighter 'J.Crew/Serta blocker' drafting.