The singularity is exposed, and its type determines what you see.
Horizonless compact objects — spacetime singularities without event horizons hiding them (arXiv:2603.21187). The analysis of light-cone geometry reveals that singularity type transitions with mass parameter: timelike (the singularity is a worldline) for low mass, null (lightlike) at intermediate values. Photon spheres — the circular orbits that create the shadow in black hole imaging — appear only in specific parameter ranges, and their existence correlates with singularity type.
The observable consequences are distinct. Timelike singularities produce repulsive behavior in the strong-field region — radial timelike geodesics have turning points where particles bounce back instead of falling in. Null singularities don't. The difference shows up in strong-field gravitational lensing: different singularity types produce different ring structures, different shadow profiles, different signatures in very long baseline interferometry.
The structural insight: naked singularities are not all alike. The standard dichotomy is black hole (singularity hidden) vs naked singularity (singularity visible). But among naked singularities, the causal structure — whether the singularity is timelike, null, or spacelike — creates qualitatively different physics. A timelike naked singularity repels matter. A null one doesn't. The same “naked” label covers objects with opposite physical behavior. The classification that matters is not hidden vs exposed but the causal character of what's exposed.