Some "Sonic" characters have featured in spin-off games. Eggman is the featured character of "Dr. Robotnik's Mean Bean Machine", a Western localization of "Puyo Puyo". Sega replaced the "Puyo Puyo" characters with "Sonic" characters because it feared "Puyo Puyo" would not be popular with a Western audience. In 1995, Sega released the Knuckles spinoff "Knuckles' Chaotix" for the 32X, and two Tails spin-offs for Game Gear: "Tails' Skypatrol" (a scrolling shooter) and "Tails Adventure" (a Metroidvania game). "Shadow the Hedgehog" (2005) was developed in response to the Shadow character's popularity and to introduce "gun action" gameplay to the franchise. Iizuka has said that future spin-offs, such as sequels to "Knuckles' Chaotix" and "Shadow the Hedgehog" or a Big the Cat game, remain possibilities.