Shadow the Hedgehog is a 2005 platformer game developed by Sega Studios USA and published by Sega. It is a spinoff from the Sonic the Hedgehog series starring the character Shadow. It follows the amnesiac Shadow's attempts to learn about his past during an alien invasion. Gameplay is similar to previous Sonic games, featuring fast-paced platforming and ring collecting, but introduces third-person shooter and nonlinear elements. Shadow uses a variety of weapons to defeat enemies and complete missions that determine the plot and playable levels.