I found some in a book about Wang Bi's commentary on the Laozi, The Craft of a Chinese Commentator: Wang Bi on the Laozi by Rudolf Wagner. Wang Bi was a young hotshot who wrote some brilliant commentaries before dying in his early 20s. According to Wagner, Wang criticized big-name commentator Zheng Xuan in a "thinly veiled" passage of his I Ching commentary. Wagner relates a story from the Shishuo Xinyu:
When Wang Bi wrote his Commentary on the Zhouyi he made fun without qualms of [a scholar as important as] Zheng Xuan because of his Ru-theories, saying, "This old fuddyduddy is completely without brains." Thereupon he heard, in the middle of the night, suddenly steps outside the door, and a moment later something stepped forth and introduced itself: Zheng Xuan. [The ghost of Zheng] accused him: "You are so young how dare you poke holes into my writings and pick at my phrases, going so far as make fun of this old man [me, ironically Zheng Xuan calls himself laozi 老子]?" He looked very angry and left straight away. Fear and worry rose in Wang Bi's heart. After a short while he fell sick and died.