How did I, who just ascended to heaven, become an evil spirit?

Pure energy rises, turbid energy descends. Some can refine the pure and purify the turbid, ascending to immortality, while others inevitably accumulate filth and decay, becoming burial objects and evil spirits. The balance of purity and turbidity is constant; this is the way of Yin and Yang. ... Li Hu began cultivating immortality at three, inquired about the Dao at five, formed his elixir at nine, and achieved immortality at twenty. He thought he had accomplished great things, but when he opened his eyes today, he exclaimed, "Damn it! How did I become an evil spirit?!"