Mari Collingwood is a fictional character from the horror film series The Last House on the Left. She is portrayed as a young woman who becomes a victim of a violent crime while on a trip with her friend. Her character is central to the film's plot, which explores themes of revenge and justice. In the story, Mari's parents, John and Emma Collingwood, seek to avenge her brutal treatment after she is kidnapped and assaulted. The film raises moral questions about the lengths to which individuals will go to protect their loved ones and the consequences of violence.