Comeback improves ink efficiency, ink recovery rate, mobility, and Special Gauge fill rate for the first 20 seconds after respawning, caused by getting splatted by another player. It is restricted to headgear as a main ability and cannot be rolled as a sub ability.
This ability is found as the main ability only on headgear, so other abilities found only on headgear are mutually exclusive with it; in other words players cannot have them together. These abilities are Last-Ditch Effort, Opening Gambit, and Tenacity.