Flint Marko (Earth-21399)

Early Life
Raised poor in Jersey City and lacking many job opportunities, Flint Marko turned to crime at an early age, making most of his money from menial jobs and gas station robberies. At some point, he married a Mexican immigrant named Emilia Alvarado, who convinced Flint that he needed to make a new future for himself. Following her advice, Flint gave up his life of crime and had a daughter with Emilia named Penelope, whom he affectionately called "Penny" and often took out to the beach to play in the sand.

Return to Crime
Flint's life was thrown into chaos when Penny developed cancer at the age of six. Flint's meager income from his lifeguard job proved insufficient to cover the medical expenses, and this sent Emilia on a downward spiral. Desperate to save Penny, Flint felt he had no choice but to return to a life of crime. Flint found work with a crew of bank robbers as the gunman, alongside safecracker Herman Schultz.

His most lucrative job was a heist on an OsCorp shipment that yielded a stash of advanced prototypes - among them a device called the Seismic Harness Construction Resource, a wrist-mounted device that fired controlled shock waves, intended for use in building demolition.

Flint's employer, Wilson Fisk, wanted to sell the cargo as part of his weapons trafficking operation, but Schultz saw greater potential in the SHCR gauntlets, and wanted to use them as gear for an even bigger heist on OsCorp itself, even convincing Flint that the building might contain resources with which to cure Penny. However, Fisk saw Schultz's ambition as a potential liability and made an example of him and his crew by sending an anonymous tip to police, who swiftly arrested them all. When Emilia found out that Flint had returned to crime, she filed for divorce and took full custody of Penny.

Becoming the Sandman
Flint was furious to hear of the divorce. When Schultz staged a prison break with his homemade SHCR gauntlets, Flint managed to escape. While on the run from the police, however, he accidentally fell into an experimental particle accelerator that fused his molecules with those of sand, turning him into a living heap of sand, capable of altering itself to achieve any form he wished.

Believing he had been given a second chance, Marko returned to New York City to resume his crime spree.