The rat who slept in Ron’s bed
Ron’s rat Scabbers is Peter Pettigrew. The rat has been hiding in the Weasley family since he faked his death and left Sirius to Azkaban.
Setup
1Harry Potter and the Prisoner of Azkaban · The rat’s odd long life
Scabbers is old, missing a toe, and suddenly declining. Ron treats that as a sick pet. Hermione’s new cat is obsessed with the rat, which looks like an animal quarrel until the Shrieking Shack.
Payoff
Harry Potter and the Prisoner of Azkaban · The Shrieking Shack
Sirius and Lupin force the rat back into a man. The missing toe matches the finger Pettigrew cut off to fake his death. He has been the Weasleys’ pet so he could wait near a wizarding family, and near Harry, without being looked at.
The same man, under the name Wormtail, returns to Voldemort and is still in his service in the later books.
People in this thread
6
Harry Potter
Student
GryffindorStudent
Ron Weasley
Student
GryffindorStudent
Hermione Granger
Student
GryffindorStudent
Sirius Black
Marauder and godfather
GryffindorOrder of the Phoenix
Remus Lupin
Teacher and werewolf
GryffindorProfessorOrder of the Phoenix
Peter Pettigrew
Marauder and traitor
GryffindorDeath Eater