Simon Stagg is a fictional character appearing in American comic books published by DC Comics, serving primarily as an antagonist to the superhero Metamorpho in most comic book stories and their adaptations. He is responsible for turning Rex Mason into Metamorpho out of spite after catching him in a relationship with his daughter Sapphire Stagg. The character has made several appearances in media outside of comics, such as the television series The Flash in which he was portrayed by William Sadler, and the DC Extended Universe film Wonder Woman 1984, in which he was portrayed by Oliver Cotton.