Dudley Dursley
Background
Dudley Dursley is a resident of 4 Privet Drive, Little Whinging, Surrey. He is the son of Aunt Petunia Dursley and Uncle Vernon Dursley. Harry Potter is his cousin.
During the events of Harry Potter and the Sorcerer's Stone (2001) played by Harry Melling
Aunt Petunia bangs on the door of the cupboard under the stairs where Harry is kept and tells him to wake up. Dudley runs down the stairs but stops to repeatedly jump up and down on the stairs above where Harry is kept. Dudley counts his birthday presents and starts yelling when he notices there is one less than the year before. After Dudley bangs on the glass of the Burmese python exhibit, Harry apologizes to it and notices it seems to understand him as he talks. Dudley sees the snake moving and shoves Harry aside and Harry makes the glass disappear. Dudley falls into the snake exhibit and the Burmese python tells Harry thanks as it slithers away. A Hogwarts owl drops off a piece of mail addressed to Harry. Dudley sees Harry looking at his letter and takes it from him and gives it to Uncle Vernon who keeps it when he notices it is from Hogwarts. Day after day, more letters arrive from Hogwarts, which Uncle Vernon continues to rip up or burn. On Sunday, the Dursley house is flooded with letters from Hogwarts and Uncle Vernon decides they are going to leave. They go to a remote shack to live and on Harry's 11th birthday, Hagrid shows up and gives Harry a birthday cake. Hagrid introduces himself to Harry and tells Harry he is a wizard, before handing Harry his acceptance letter from Hogwarts. Uncle Vernon tells Hagrid, Harry will not be going to Hogwarts and Aunt Petunia insults Harry's mother Lily Potter. Uncle Vernon insults Albus Dumbledore and Hagrid makes Dudley grow a pig tail when he sees Dudley eating Harry's birthday cake. Hagrid and Harry then leave and go to London.
During the events of Harry Potter and the Chamber of Secrets (2002) played by Harry Melling
Uncle Vernon, who is fixing Dudley's tie, tells Harry he better control Hedwig. After dinner with Mr Mason and Mrs Mason, Harry seemingly drops Aunt Petunia's cake on Mrs Mason's head.