Slither is a 2006 science fiction comedy horror film written and directed by James Gunn in his directorial debut. Produced by Paul Brooks and Eric Newman, the film stars Nathan Fillion, Elizabeth Banks, Tania Saulnier, Gregg Henry, and Michael Rooker. The film is set in a small town in South Carolina that becomes invaded by a malevolent alien parasite.

Slither was theatrically released in the United States and Canada on March 31, 2006, by Universal Pictures and TVA Films respectively. The film received generally positive reviews from critics, who deemed it funny and creepy, while praising its premise, B-movie conventions, Gunn's direction, script and the performances of the cast. However, it was a box office failure, grossing only $12 million worldwide against a $15 million budget.