E-10000B is an Extreme Gear racing robot built by Dr. Eggman that appears as a playable character in Sonic Free Riders, replacing E-123 Omega as Team Dark's Power Type character. He shares the same base model design as E-10000G and E-10000R, and appears to be on the same frequency as E-10000G. He is only playable in the World Grand Prix mode, as E-10000G takes his place in the multiplayer mode.
Shadow and Rouge have just come for the World Grand Prix and attempted to join. However, Omochao refused the two because they needed three members in order to participate. Rouge then randomly picked E-10000B who agreed to join their team. After a little while, E-10000B complained that he was tired, but was selfishly ignored by his teammates. Later on, E-10000B malfunctioned, broke down, and appears to explode. This exposed him as his true identity: Metal Sonic. It is unknown if E-10000B was a disguise for Metal Sonic or if Metal Sonic somehow got inside and took control of him.
| Characters in the Sonic the Hedgehog game series
||Sonic (Super, Hyper, Darkspine, the Werehog, Excalibur) | Tails (Super) | Knuckles (Super, Hyper) | Amy Rose | Cream | Big | Blaze (Burning) | Emerl | Silver (Super) | Marine | Lumina Flowlight | Chip | Shahra | Knights of the Round Table | Caliburn | Yacker | Sticks | Avatar
||Shadow (Super) | Rouge | Espio | Charmy | Vector | Mighty | Ray | Chaos (Perfect) | E-102 Gamma | E-123 Omega | Bean | Bark | Jet | Wave | Storm | Shade | Merlina
||Dr. Eggman | Metal Sonic (Kai, Rocket, Neo, 3.0) | Mecha Sonic (Super) | Fang | Witchcart | Battle Kukku Army (15th, Speedy, Dr. Fukurokov) | Tails Doll | Metal Knuckles | E-Series | ZERO | Void | Biolizard | Gemerl | Eggman Nega | Black Doom | Angelus | Iblis | Mephiles | Solaris | Erazor Djinn | Captain Whisker | Johnny | Master Core: ABIS | Ix (Super) | Dark Gaia | King Arthur | Orbot | Cubot | Deadly Six (Zavok, Zazz, Zomom, Master Zik, Zeena, Zor) | Hard-Boiled Heavies | Infinite
|| Sonic/Heroes | Rose | Dark | Chaotix | Babylon
|| Gerald & Maria Robotnik | Froggy | Chao | Omochao | Cheese | Chocola | Vanilla | Tikal | Pachacamac | E-101 Beta | Illumina | President | G.U.N. Commander | Elise | Duke of Soleanna | Coconut Crew | Vikings | Professor Pickle | Wentos | Don Fachio | Heavy and Bomb | Tiara Boobowski | Honey | Flicky | Animals | Wisps