Is “In Buddhism, there is no allusion to a black bear spirit transforming into the guardian mountain deity.” true?

In Chapter 017 of 'Journey to the West', the Black Bear Spirit of Black Wind Mountain steals the cassock and is later subdued by Guanyin Bodhisattva to become the guardian deity of Mount Luojia in the South Sea. There is no record of this black bear in orthodox Buddhist dharma protection; it is an original monster turned righteous in the novel. Original text: "我那落伽山后无人看管，我要带他去做个守山大神。" (Chapter 017 of 'Journey to the West')