Harry Potter and the Prisoner of Azkaban attacked by a big black dog, which Harry has seen several times before. The dog drags Ron through a tunnel under the Whomping Willow into the Shrieking Shack. Harry and Hermione follow, and there is a brief standoff when they find Ron with Sirius Black, who has transformed from the dog. Lupin enters, and they explain the situation to Harry and his friends: Lupin is a werewolf, which led to his friends James Potter, Sirius Black, and Peter Pettigrew becoming animagi. Lupin explains that Scabbers is Pettigrew in his animal form; he has been hiding from Black, whom he had
Harry Potter (film series) second unit, and the visual effects unit. You have to know what is being captured – colours, contrast, et cetera – with mathematical precision." He noted that with Stuart Craig's "amazing sets and the story", the filmmakers could not "stray too far from the look of the previous "Harry Potter" films." Along with continuous changes in cinematographers, there have been five film editors to work in post-production on the series: Richard Francis-Bruce edited the first instalment, Peter Honess the second, Steven Weisberg the third, Mick Audsley the fourth, and Mark Day films five through eight. The "Harry Potter" series has