Stuffed Sonic

 is a Japanese-American adventure-science fiction video game series, serving as a spin-off to the  series, being developed by Sonic Team and published by Sega since April 23rd, 2011.

Synopsis
Set in a world where every character are stuffed animals, Sonic explores Mobius and combats threats.

First game
Sonic has to run around worlds to collect the Seven Chaos Emeralds before Eggman uses them in order to conquer the world.

Stuffenstein Strikes
A mysterious cult has been stealing ancient devices to summon a monster called Stuffenstein as Sonic has to collect New Chaos Emeralds to stop this beast and his monstrous inventions.

Looming Darkness
Sonic encounters a mysterious new hedgehog as the both soon have to reluctantly work together when a cosmic entity forms an alliance with Eggman, boosting his Badniks and rewriting the Chaos Emeralds' abilities.

Two Worlds
A simple battle between Sonic and Eggman becomes dimensional as Sonic is thrust to a mysterious new world terrorized by a pirate named Whiskers as he works with two figures from this world to defeat Whiskers.

Into the Lost World
Sonic has been relaxing until a race of super creatures known as the Zeti have been summoned by Eggman, forcing Sonic to figure out where they come from and what they truly want.

Games

 * 1)  (video game) (2011)
 * 2)  Stuffenstein Strikes (2013)
 * 3)  Looming Darkness (2016)
 * 4)  Two Worlds (2018)
 * 5)  Into the Lost World (2020)

Main

 * Sonic the Hedgehog (voiced by Jason Marsden) - a friendly and adventurous blue hedgehog with superhuman speed who is out to protect his world from villainous threats.

Supporting

 * Miles "Tails" Prower (voiced by Grey Griffin) - an intelligent twin-tailed fox who is Sonic's best friend and helps him by providing useful gadgets on his journey, even if, much to his annoyance, they often malfunction or backfire at him.
 * Knuckles the Echidna (voiced by Charlie Schlatter) - a stoic and TBD echidna who guards the Master Emerald as he occasionally joins Sonic on adventures, even if he fears that the Master Emerald might be vulnerable to any kind of thieves.
 * Amy Rose (voiced by Jessica DiCicco) - a TBD female hedgehog who is another of Sonic's close friends as she wields a mallet that allows her to smash any kind of obstacle while trying to gain confidence to ask him out.
 * Cream the Rabbit (voiced by Tara Strong) - a TBD preteen female rabbit who is Amy's best friend and, despite her age, is pretty knowledgeable about Chaos and other elements, having a crush on Tails as well.
 * Cheese the Chao (vocal effects by Tara Strong) - TBD
 * The Chaotix, consisting of:
 * Vector the Crocodile (voiced by Townsend Coleman) - TBD
 * Espio the Chameleon (voiced by Dante Basco) - TBD
 * Charmy Bee (also voiced by Grey Griffin) - TBD
 * Tikal the Echidna (voiced by Alanna Ubach) - a friendly female echidna who guards the Chao Garden and is an old friend of Knuckles as she provides Sonic with a way to take care of Chaos.
 * Big the Cat (voiced by John DiMaggio) - TBD
 * Vanilla the Rabbit (voiced by Jennifer Hale) - TBD
 * Shadow the Hedgehog (voiced by David Faustino) - TBD
 * Rouge the Bat (voiced by Olivia Olson) - TBD
 * E-123 Omega (voiced by Jim Meskimen) - TBD
 * Silver the Hedgehog (voiced by Jack DeSena) - TBD
 * Blaze the Cat (voiced by Jessica McKenna) - TBD
 * Marine the Raccoon (voiced by Ashley Johnson) - TBD
 * TBD

Antagonists

 * Dr. Ivo "Eggman" Robotnik (voiced by Nolan North) - a vicious mad scientist who created an army of robots on his quest to take over Mobius as TBD.
 * Orbot and Cubot (voiced by Rodger Bumpass and Richard Steven Horvitz, respectively) - Eggman's loyal but snarky henchbots who spend more time questioning their master's motives rather than actually helping him.
 * Metal Sonic (also voiced by Jason Marsden) - a robotic doppelgänger of Sonic created by Eggman to outmatch him, gaining self-consciousness and becoming obsessed to replace him as the one and only Sonic.
 * Stuffenstein (voiced by David Sobolov) - a giant ancient monster made out of various stuffed Mobians as he wants to conquer Mobius.
 * Black Doom (voiced by Tom Kane) - TBD
 * Captain Whisker (voiced by Mark Hamill) - TBD
 * The Deadly Six, consisting of:
 * Zavok (voiced by Dave Boat) - TBD
 * Zazz (voiced by Jason Spisak) - TBD
 * Zeena (voiced by Kari Wahlgren) - TBD
 * Master Zik (voiced by Keone Young) - TBD
 * Zomom (voiced by Kevin Michael Richardson) - TBD
 * Zor (voiced by Josh Keaton) - TBD
 * TBD

Recurring enemies

 * Moto Bug - TBD
 * Eggrobo - TBD
 * Egg Pawn - TBD
 * Buzzer - TBD
 * Crabmeat - TBD

Gameplay
The games play as puzzle games as you play as Sonic and solve several puzzles in various worlds. Each world gives you a Chaos Emerald that serves as a tool to help with several puzzles with each having different abilities. Bosses also take a puzzle-like route as you have to use the world's Chaos Emerald and prior Chaos Emeralds to beat it and use it to solve puzzles embedded into the boss. Sonic is capable to defeat enemies by either jumping on them, using the Chaos Emeralds or using the environment.

The games also have a Chao Garden mechanic where TBD.

Items

 * Rings - a common currency that can be used to buy various things in the shop.
 * Red Star Rings - a premium form of Rings which are more valuable than rings.
 * Health Add-Ons - potions which Sonic can find hidden in levels as when he drinks them, he gets an additional heart.
 * Chaos Drives - miniature devices spread across levels which can be used to help raise Chao in the Chao Garden.
 * Fruits - a delicious delicacy which can be bought in the shop as it can be used to also help nurture Chaos.

Introduced in the first game

 * Gravity Emerald - a Chaos Emerald that allows Sonic to manipulate gravity around him to move obstacles and enemies up.
 * Flight Emerald - a Chaos Emerald that allows Sonic to float up to the sky, allowing him to reach items and areas he can't reach.
 * Water Emerald - a Chaos Emerald that allows Sonic to breath under water.
 * Telekinesis Emerald - a Chaos Emerald that allows Sonic to move objects and enemies anywhere, being considered to be a more powerful Gravity Emerald.
 * Invisibility Emerald - a Chaos Emerald that allows Sonic to turn invisible and avoid being detected.
 * Shrink Emerald - a Chaos Emerald that allows Sonic to shrink down to a miniature size, allowing him to go to places he normally can't go.
 * Phase Emerald - TBD

Trivia

 * To differentiate it from the Prime series, the characters have a chibi look that resembles their pre-Adventure designs in size while still designed to resemble their modern counterparts, facial features and clothing included, and different voices in order to make them distinct from their Prime ones.

Easter eggs

 * One of Eggman's blueprints resembles a dragon from Panzer Dragoon.
 * Green Hill's arcade has several classic Sega arcade games, most notably House of the Dead.
 * [Baka Mitai karaoke]
 * Nights appears on a poster in a level.
 * In Two Worlds, Sonic was drinking a slush with Morgana's face on it.