Tails' Skypatrol

Included in Sonic Adventure DX: Director's Cut & Sonic Gems Collection.

The game was never released outside of Japan. The game is a spin-off and a prequel to the Sonic series following the adventures of Sonic's trusty sidekick Tails the Fox as he tries to save an island from Wendy Witchcart, who turns anyone opposing her into crystals with her magic and before meeting Sonic.