ΛCDM picture Substrate picture DM halo TDG forms here DM stays in halo No dark matter! ? TDG escapes halo → should show no DM enhancement ✗ Contradicts observations dc1 substrate fills all space TDG forms here Substrate IS the DM Immersed in DM Same boundaries → same MOND response TDG never leaves the DM → same boundary physics as every other galaxy ✓ Matches observations