David Dunn is a fictional character from the 2000 film Unbreakable, directed by M. Night Shyamalan. He is portrayed by actor Bruce Willis and is a security guard who discovers he has superhuman abilities after surviving a train crash without a scratch. In the film, Dunn's journey leads him to meet Elijah Price, played by Samuel L. Jackson, who believes that Dunn is a real-life superhero. The story explores themes of identity, strength, and the nature of good and evil, setting the stage for a unique take on the superhero genre.