Who transformed into a shape-shifting Sandman in "Spider-Man 3"?

Flint Marko transformed into the shape-shifting Sandman in “Spider-Man 3.”

Marko is introduced as a criminal who escapes custody and accidentally falls into an experimental particle accelerator. The accident alters his body, allowing him to dissolve into sand, reshape himself, grow enormous, and create powerful sand-based attacks. Thomas Haden Church played the character in the 2007 film.

Sandman is not simply a new identity invented by the accident. In the film, Marko is already a desperate criminal, and his transformation complicates Spider-Man’s view of him. Peter Parker initially believes Marko killed Uncle Ben, but Marko later reveals that the shooting was accidental and expresses remorse.

A common mix-up is confusing Marko with Eddie Brock, who becomes Venom in the same movie. Sandman’s abilities come from the accelerator accident, while Venom is an alien symbiote that bonds with Brock. In Marvel Comics, Sandman is also known as William Baker, although the film uses Flint Marko as his civilian name.