From Sonic Retro
The E-10000G is a mass-production Extreme Gear racing robot developed by Dr. Eggman. It accounts for most of the Doctor's robotic minions deployed during Sonic Riders, and also appears in Sonic Free Riders. These green-painted machines compete against Team Sonic and the Babylon Rogues in races of the EX World Grand Prix and beyond. It is a playable character in free race or multiplayer modes, unlocked by either playing 100 races or clocking up over 20 hours of play-time.
E-10000G is ostensibly a Power type racer, although opponent models in the Story Mode can use Speed and Flight type skills as well. Multiple copies of the robot appear as opponents in almost every EX World Grand Prix race in the game, with the exception of the final in Sand Ruins or Dark Desert. They also follow their master to continue racing against Jet and Sonic aboard the Babylon Garden.
The E-10000G models have headgear that looks remarkably like backwards baseball caps. They are generally more humanoid than earlier E-series robots like the E-100s, although they neither speak nor demonstrate having the kind of self-awareness exhibited by E-101 Beta or E-102 Gamma. They defer to E-10000R, who commands them to attack Knuckles and Storm just before Sky Road.