The Extraordinary Supernatural
In contrast to the ordinary supernatural, the extraordinary supernatural is either not understood, seldom occurring or rarely mentioned in the collection. It is usually not directly related to human destiny and not of practical benefit to society.
Particular Creatures and Phenomena
Nearly one third of all biji mention extraordinary supernatural beings and phenomena, that are said to be unusual and unexplainable. Included are creatures that are familiar but simply rarely alluded to, like immortals or fairies. Moreover, some beings are a mixture of different known kinds or defined as 'standing between humans and creatures', like the supernatural foxes and yakshas 夜叉. Ji Yun comments that there are yakshas in the ocean as there are mountain demons in the mountains. Yakshas are neither ghosts nor demons, but a category on their own, standing between humans and beasts: "海之有夜叉，猶山之有山魈，非鬼非魅，乃自一種類，介乎人物之間者也" (RS II.10).
Demonic Creatures and Apparitions
Unlike other supernatural beings, demonic apparitions are all understood as harmful for humans. They are frequently named mei 魅 or yao 妖. Mei is originally a female tree spirit (dryad), or a creature with four legs and a human face, which has developed out of the qi 氣 of forests and mountains; while yao is a malicious spectral being, which bewitches humans. It is a mischievous and wayward demonic apparition, with bad influence on the environment. Sometimes, a demon is also termed mo 魔, jingshen 精神, or shenwu 神物. All objects as well as living beings can become demonic by gathering an increasing amount of energy over a long period of time and thus gain supernatural power. Moreover, nearly everything can be used as a physical cover by a demon. Like ghosts, they consist of yin-energy and can be driven out or destroyed by yang-energy.
Early narratives describe magic foxes as threatening demonic creatures, living in graves and decayed houses. In the course of time, however, they became less frightening, until finally they were domesticated and turned into an integrated part of human culture. In stories from the Qing dynasty, they stay closer to humans and frequently reside in the attic, a garden pavilion, or a pile of firewood.
It is believed, that the magical abilities of foxes increase with age. From a certain age onward, they can transform into irresistibly beautiful women in order to seduce men. An explanation for this is the popular belief, that foxes always aim at becoming immortal 仙 and turn into a heavenly fox 天狐, which they can accomplish by gathering human seminal essence 精氣. Traditionally the character of foxes is pictured as insincere, cunning, vengeful, and refractory. Nonetheless, or maybe because of this, later stories frequently tell of humans and foxes living together, being friends, or having a harmless love affair. Their supernatural abilities notwithstanding, foxes are always inferior to dogs, can be cast out by humans with magical powers, or simply shot dead.