Giant mutant mole people

Two Giant Mutant Mole People appear in "Arthur's Lost Library Book". Buster theorized that the mole people stole Arthur's library book, but Arthur disregarded the idea. Right beneath their feet, two mole people were listening in on them with a hearing machine. They both denied having the book.

Despite some normal characters being moles, they are regarded as fictional by the kids. They also have noses more similar in shape to rats than moles, and even have the skin color of a rat student.