A dog less threatening than it seems
Sirius Black is Harry Potter’s godfather in the famous literary and cinematographic saga of the same name. We discover his existence in the third opus of the saga when he escapes from Azkaban prison. Indeed, he was locked up there after being found guilty of giving the location of Lily and James Potter to Voldemort, causing their premature death when Harry was only one year old. Everyone at school and at the Ministry of Magic is convinced that he will try to get back at Harry, finding him guilty of his incarceration. This seems to be the case when he is seen around the castle and even manages to infiltrate the Gryffindor common room. But the reality is not what it seems because Sirius was actually after Ron’s rat who happened to be Peter Pettigrew, another friend of James and Lily’s who sold them to Voldemort and then took on the appearance of a rat in order to frame Sirius. Peter manages to escape and Sirius has to stay on the run, but at least Harry knows that his sponsor is a good person. In order not to be spotted, Sirius takes on the form of a black dog several times since he is like Peter and Harry’s father an animagus, a wizard who can take the form of an animal.