From Sonic Retro
Unarmed Egg Fighters roam around, approaching Sonic if they spot him. They attack by using a spinning move with their arms outstretched. They resemble a cross between SatAM / Sonic Chronicles' SWATbots and the Egg Pawns from previous Sonic games, while expanding on their arsenal of weaponry and accessories. Even when destroyed, Egg Fighters may keep fighting; some of the robots have modified, autonomous hands, which attack from the wreckage as Little Fighters.
While the vast majority of Egg Fighters are purple-blue, a few red colored units appear in the very first stage, Windmill Isle Day Act 1.
Egg Fighters and their Sword sub-variants reappear in Rooftop Run in HD Sonic Generations.