Since 2195, Tessera Arcology Seven has experienced 142 documented incidents of luminous spherical phenomena — colloquially referred to as ball lightning by residents, though the designation is inaccurate. Ball lightning is an atmospheric phenomenon. These objects appear inside sealed, climate-controlled sectors with no atmospheric variability. They drift through corridors, pass through walls, and dissipate after periods ranging from twelve seconds to seven minutes. They emit light in a spectrum that does not match any known plasma state.

The objects are not consistent in size — ranging from 8 centimeters to nearly a meter in diameter — but they are consistent in behavior. They move at approximately walking pace. They navigate around obstacles. They do not collide with people, though they have passed within centimeters of residents on multiple occasions. Three residents report that the objects paused in their presence, as if observing. This characterization is anthropomorphic and unsupported by any data suggesting the objects possess awareness. It is also the characterization used by all three residents independently.

The phenomena correlate with grid surges in the arcology's power distribution system. Every documented appearance occurs within 90 seconds of a measurable power fluctuation. The fluctuations are small — within normal operational variance — and do not trigger any alarm or safety system. Whether the surges cause the phenomena or the phenomena cause the surges has not been determined.

Capture has been attempted eleven times using electromagnetic containment, Faraday enclosures, and physical barriers. The objects pass through all containment methods as if they are not there. They interact with the visual spectrum — they emit visible light, they cast shadows that move independently of the light source — but they do not interact with matter. They are things that can be seen but not touched, that navigate intelligently through a sealed building, and that vanish leaving no residue, no burn mark, no electromagnetic trace. Tessera has stopped attempting capture and begun attempting to pretend they don't exist.