What the hell is a ghost fire?

On summer nights, blue-green flames sometimes appear in the suburbs or near ancient tombs, looming and erratic. There used to be a legend in the countryside that people would become ghosts after death. Ghosts are afraid of light and dare not come out during the day, but only appear at night. In the cemetery or wilderness, sometimes there will be green or light blue flame clouds at night, jumping infinitely. What's even weirder is that it will follow people, stop when you stop, and follow you when you run. Superstitious people say that this is a kind of "ghost fire" for ghosts to go out at night, and they also describe it as a ghost lamp in Yan Luowang. In Strange Tales from a Lonely Studio by Pu Songling, a writer in Qing Dynasty, people often talk about it.

In fact, this is caused by phosphorus. It turns out that both human and animal bodies (animal bones in rural areas and human bones in graves after death) contain phosphorus, which is neither white phosphorus nor red phosphorus, but exists in the form of phosphorus compounds. People and animals are buried underground after death, and their bodies rot. After long-term scorching sun and rain and dew leaching, phosphorus compounds gradually penetrate into the soil and decompose to form phosphine.