Ron′s rat is in fact Peter Pettigrew who is an animagus, too. Ron, Harry and Hermione are stunned and disbelieving after this revelation. Harry learns the whole story about the betrayer Pettigrew and his godfather Sirius Black. Furthermore he gets to know that Peter Pettigrew, Sirius Black and his father have been unregistered animagi who often transformed while still being at school to stay with Remus Lupin during his monthly time as a werewolf.
Suddenly Professor Snape shows up and misunderstands the whole situation. The secret of Peter Pettigrew is still not revealed.
