Rogue bludger

Dobby's bludger was created during the 1992-1993 school year. It's purpose was to injure Harry Potter so that he would be (hopefully) sent home from Hogwarts. The Chamber of Secrets was active and petrifying students at the time. The Bludgercaused the Gryffindor beaters to protect Harry and not watch out for the rest of the team. Despite their attempts, the bludger succeeded in breaking Harry's arm. Dobby later apologised for setting it on Harry.

Appearances
Harry Potter and the Chamber of Secrets Harry Potter and the Chamber of Secrets (film)