The Canis Major overdensity has spent twenty years suspended between identities: announced as a disrupting dwarf core feeding the Monoceros Ring, hierarchical accretion caught mid-meal, yet repeatedly reanalyzed as the warped, flared outer disk seen edge-on, with populations and kinematics reading disk-like and no clean orbital family isolated. Either answer costs ΛCDM: an accretion event that resists reconstruction, or a showcase devoured and replaced by an unexplained warp.
The model wants low-latitude substructure to be accretion debris, because hierarchical assembly is its engine and the warp has no first-class cause of its own: warps in ΛCDM are reactive afterthoughts of satellite torques and misaligned infall. The framework must therefore classify every disk-edge excess against a binary, foreign or bent, that its own machinery makes hard to score.
SCT dissolves the binary: in a galaxy condensed from a rotating debris field, in-plane overdensities and a bent outer disk are not rival explanations but siblings. The disk inherits its angular momentum from the collision geometry (P31, P32), and the outer disk, where local self-gravity weakens, responds to the parent-frame mesh's tidal field, misaligned with the inner disk's J, producing the warp as a standing inherited feature rather than a reactive accident (P51). Debris-stream condensations within the same deposition, the Canis Major excess and the Monoceros family, ride the warped edge as in-plane substructure with disk-like chemistry and kinematics, exactly the hybrid signature that frustrates the accreted-versus-warp classification.
The prediction is continuity: SCT expects the overdensity to share the disk's chemical gradients and rotation with modest local distortion, aligned with the warp geometry and the larger local J structure, never resolving into a distinct bound progenitor with its own orbit family. Twenty years of failed progenitor reconstruction is the expected outcome, not an embarrassment deferred.
This is the same inherited-structure reading behind the Monoceros Ring and the satellite-plane geometry. There is no need to force the disk's edge into a foreign-or-bent binary built for a different formation story.
The classification is decidable: Gaia and spectroscopic surveys isolating a coherent orbital family with distinct chemistry, a genuine bound-progenitor signature with a reconstructed orbit linking Canis Major to a tidal stream, would establish the accretion reading and remove the deposition account. The warp adds its own test: SCT requires the warp orientation to align with the local inherited J structure (satellite plane, warp, and local flow geometry correlated); demonstrated misalignment of these vectors at high confidence breaks the shared-deposition picture.