Sandman

Used Flint Marko as an alias so his mother wouldn’t know he was a criminal
Exposed to irradiated sand at a nuclear testing site on a beach;
Turned his body into sand, often fought with & defeated by Spider-Man
Became a member of the Sinister Six, sometimes allies himself with Hydro-Man
Grew tired of a life of crime, redeemed himself over time, eventually becoming an antihero