|Book(s)||Fire & Blood (mentioned)|
Character and Appearance
He was described as a simpleton. He was clumsy and prone to tremors.
Tom Turnip was a fool in the court of King Jaehaerys and Queen Alysanne. Their daughter Saera Targaryen often played cruel pranks on Tom, such as once telling him it would amuse the court if he performed naked - which it didn't - or telling him that if he climbed the Iron Throne he would become king - slicing his arms and legs to pieces in the process.
In 84 AC Braxton Beesbury, Jonah Mooton and Red Roy Connnington were found drunk at the Blue Pearl, a brothel in King's Landing, laughing as the king's fool, Tom Turnip, was surrounded by whores. When asked by men of the City Watch, Roy admitted they thought it would be funny to see the fool do the deed. One of the watchmen overheard Princess Saera name being mentioned by the drunken youths. It turned out later that the whole incident had been the Princesses idea as a jape against the fool. The event led to unforeseen troubles for the princess though. 
- Fire & Blood, The Long Reign - Jaehaerys and Alysanne: Policy, Progeny, and Pain.