The answer is the mystery of Scorpio.

The indomitable spirit has a shadow, but it is invisible to cows, dogs, dragons and snakes. It is necessary to be able to treat diseases.

Analysis: the first sentence tells him that there is a word in "indomitable spirit", and the second sentence shows that this constellation is an animal, but not a cow, dog, dragon or snake; The third sentence shows that it is a worm, which can be used as a medicine guide, and the fourth sentence points out that the time is in autumn;

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