Joke book (Knock! Knock! Who's There?)
From Tardis Wiki, the free Doctor Who reference
The Thirteenth Doctor and Yasmin Khan once found themselves trapped inside a joke book.
The jokes contained several jokes and comedic stories featuring the Doctor's various incarnations, companions, and enemies from across their life.
The Doctor and Yaz were able to escape from the book after finding the oldest joke in the universe. (PROSE: Knock! Knock! Who's There?)
