Eustace’s inability to resist pulling on Reepicheep’s long tail is an early instance of temptation in the book. As a mouse, Reepicheep is small and therefore the only one on the boat that Eustace can bully—or so Eustace thinks. While Eustace thinks that he has finally found someone weaker to pick on, he learns that acting like a bully can have consequences, particularly when you mess with the wrong person (or mouse).