I got back to the dig site close to Umai's north pole. It was strangely desolate. All excavation work has stopped. Almost everyone has left, except for Mitsiro and five of his close assistants. It makes the domed surface station -now vastly over-sized for a handful of inhabitants- even more eerie.
While Mitsiro and I were considering how to obtain a black cat, news arrived from the medlab. The micro-lesions in the area of the bite appear to be consistent with an attack by a nanite swarm. This is a swarm of microscopic devices that can move in a collectively coordinated way, not unlike a bird swarm or a school of fish. They can mimic, for example, a dog. The cloud is not a solid object, so a blade would just pass through. However, the nanites can cause severe harm, both thermal and abrasive, as well as internal wounds and hemorrhaging when they are breathed in.
It all makes sense now - I have seen effects of nanite swarms on remnants of ships trying to remove artifacts from Takmahl vaults. They must have been more widespread as a defense mechanism for hidden structures built by the ancients.
Although the apparition may have been created to fool us into thinking there is a ghost in the tomb, it is very much not supernatural. A nanite swarm is not defeated by an icon of Saint Kargan or by a black cat, but by a directed electromagnetic pulse weapon. That should not be hard to obtain at the FDU Assembly Plant in orbit.
