Chinese artist Lee Yuet-fung pleaded not guilty to common assault at a Hong Kong court on March 31.

The painter was accused of throwing a cup at Lai Wing-man, a Cathay Pacific flight attendant, when she was slow to respond to his request for water during a flight from Singapore to Hong Kong on December 10, 2014.

In court this week, Lee claimed he suffers from severe diabetes and that he needed water to take his medication. He added that his hands were shaking and that he dropped the cup to the floor by accident.

Lai said the artist assaulted her with a plastic cup and that she had marks on her body to prove it. She argued that she was too busy clearing food trays and could not immediately get water for the artist. (See more artnet content on artists behaving badly — Russian Performance Artists Arrested for Exorcizing Lenin and Vagina Kayak Artist Arrested Again for Titillating New Work.)

Lee chose to represent himself in court and, according to local media, his defense was criticized by the magistrate for being faulty.

When Lee was asked to swear an oath to tell the truth in court, he did not read the official words, saying instead: “I, Lee Yuet-fung, guarantee that what Miss Lai has said is incorrect—I didn’t throw the cup.”

“Do you think this is a playground? If you disrupt court proceedings again I will place you in the dock,” responded Deputy magistrate Jim Chun-ki. The case has been adjourned until April 9 for the verdict.

Lee lives and works in Shenzhen, and is best known for his ink paintings of tigers and bamboo. He has exhibited throughout Asia, and his works are collected by Chinese officials.