Your worst enemy is your own self, as Will Smith learns in the trailer for "Gemini Man."
Ang Lee's sci-fi thriller has Smith playing dual roles: an aging assassin hunting down his younger clone. The movie uses the kind of de-aging special effects used in "Captain Marvel" to make the 50-year-old Smith look just like he did when he was 23.
"They chose me because there's never been anybody like me," the older assassin, Henry, tells "Junior." Their cat-and-mouse game is complicated by the fact that they can predict each other's moves.
The story bears similarities to Rian Johnson's "Looper," which featured Bruce Willis and a younger version of his character played by Joseph Gordon-Levitt. But that involved time travel, while this movie uses cloning.
And now, the technology has improved enough that Samuel L. Jackson was very convincing as a younger, '90s-era Nick Fury. Martin Scorsese is also using de-aging VFX in his upcoming "The Irishman" so that Robert De Niro and Al Pacino can play characters through multiple decades.
"Gemini Man" also stars Mary Elizabeth Winstead, Benedict Wong, and Clive Owen, and opens in theaters October 11.