In HP- PoA, what does Hermione refer to when she says, "I think they're funny"?

After Malfoy asks how to open the Moster Book of Monsters and Hagrid replies, he walks away. Then, you see Neville getting attacked by his copy of the Moster Book of Monsters. Next, you see Harry, Ron, and Hermione put their stuff down and Hermione says, "I think they're funny."