Phoenix and black dragon are just symbols. It is estimated that you can't see their true colors, but the intentions of the brain and nerves, which are judged according to the occasion and environment.
This dream is really good, and as you said, I suddenly found myself knowledgeable, and I know many fields of knowledge that have never been involved before. In fact, your physiological magnetic field suddenly strengthens, which leads to the integration of a lot of information you have come into contact with and forms a very strict system, which is the result of long-term learning experience.
It suddenly dawned on me that it seems that people's sixth sense has become particularly sensitive. From this point of view, you are a thoughtful person with good understanding and strong self-learning ability.
This dream is accidental and doesn't mean what will happen in the future. Don't be too happy. It may represent the result of strengthening one of your learning skills.