Zhou Chao fell ill, and everyone had fish scales on their bodies to varying degrees. The black crows seemed to be possessed by evil spirits. They caught people with fish scales and attacked them. Once they were targeted, the person would be left with nothing but bones in less than half an hour.
People were panicked for a while, until the national master observed the sky and found someone who could suppress him...
Concept: It was a dream. It felt very novel, so I wrote it down.