Sonic Armageddon

Sonic Armageddon was a planned film by Ben Hurst (writer of Sonic: The Animated Series and Sonic Underground) alongside Ken Penders, the writer of Sonic Archie comics, based on the Saturday morning cartoon Sonic the Hedgehog, and proposed to Sega in 2003.

Plot
From the looks of the storyboards, it looks like the film would be about Mobius exploiting, so it would likely serve as a sequel to the Sonic the Hedgehog animated series.

Why It Was Cancelled

 * 1) Sega was already busy with Sonic X.
 * 2) Ken Penders, in a act of sabotage, told Sega that Hurst was trying to co-opt the franchise, which is of course a lie. This caused the company to fire Hurst from the project and allowed Penders to rewrite his own story based on the Archie version and pitched it Sega before being dropped in 2007, due to "massive" corporate upheaval.

Results

 * The film was permanently cancelled.
 * Sony Pictures took over the rights to make a film, but was later sold to Paramount Pictures, which released the film on February 14, 2020.