Alan Smithee is the official pseudonym used by filmmakers who wish to disown a project. The term came about in 1968, when actor Richard Widmark enlisted director Don Siegel to complete the film "Death of a Gunfighter," after vocalizing his discontent with current director Robert Totten. Siegel's logged days on the film were less than half of Totten's, and he contended after production wrapped that the bullish Widmark was really the one in control of the project. Siegel didn't want screen credit, and Totten, understandably insulted, didn't want the credit either; Alan Smithee was born.
Other famous Alan Smithee projects include the extended version of David Lynch's "Dune," and the edited TV versions of Michael Mann's "Heat" and "The Insider." Indeed, TV cuts tend to bring a directorial wish for distance: The original television versions of Martin Brest's "Scent of a Woman" and "Meet Joe Black," and David Anspaugh's "Rudy," all ended up with a Smithee credit.
Here's the new "After Earth" trailer (with the first trailer here):