What does "wild fox cicada" mean?

Wild foxes learn Taoism, but they are circuitous, ignorant and pretend to be enlightened. Zen scholars call it "Wild Fox Zen". Here is a famous case: once upon a time, an old man was asked by an economist, "Is there a causal relationship between pedestrians who have been overhauled?" Answer: "No cause and effect." As a result, 500 people were born wild foxes. Later, Zen master Baizhang Huaihai took a turn: "I don't know the cause and effect", so the old man took off the wild fox. (See Volume III of Five Lights Meeting Yuan) It turns out that Buddhism's cultivation of cause and effect is the embodiment of the law of cause and effect. The old man thought that a man of practice could "not fall into cause and effect", but he just fell into Jaken, which was a "big lie" and was rewarded by the "wild fox". There is also a monk in Yan Rui who calls himself a "hero" all day and keeps his promise. Song criticized him for mistaking "knowing God" for "sincere" and "wild fox's view". (The Legend of No Door) Later called "Wild Fox Zen" crooked ways. For example, the eleventh time in The Scholars: "If the eight-part essay is not exquisite, no matter what you do, it is a wild fox Zen, and evil spirits are heretics."