I joked with a boy who was the shortest in the class that he was Wu Dalang. He was not angry, but instead said that I was Wu Song. What does that mean?

Actually, this is your mistake. If you have a shortcoming and love being short, you shouldn’t laugh. He is Wu Dalang, and this is the most self-esteem-damaging thing. Slap in the face. He told you that you are Wu Song, which proves that you two are her and he was joking. He meant that you are her brother