In "Spider-Man 3," the Sandman’s daughter is named Penny Marko.
Penny is Flint Marko’s young daughter, portrayed by Perla Haney-Jardine. She is seriously ill, and Flint’s desperation to pay for her medical treatment helps explain why he returns to crime after becoming the Sandman. The film uses his relationship with Penny to give the villain a sympathetic, family-centered motivation.
Penny’s mother is Emma Marko, Flint’s estranged wife. Although Flint is involved in dangerous crimes, his strongest emotional goal is seeing Penny and helping her survive. Near the end of the film, he visits Penny and asks for forgiveness, leading to a quiet reconciliation before he leaves.
A common mix-up comes from Marvel Comics, where Sandman’s daughter is generally associated with the name Keemia Marko. That is a different continuity and character history. In Sam Raimi’s 2007 film, the daughter’s name is Penny, and the full name used for the movie character is Penny Marko.