Eggrobo
From Sonic Retro
Eggrobo (エッグロボ) are android badniks who make their first appearence in Sonic & Knuckles.Sky Sanctuary Zone. Shaped like an egg with arms and legs (clearly made to resemble Dr. Eggman), Eggrobos hover in place and attack with a laser pistol. They appear to be amongst the most advanced of the Doctor's animal-containing badniks, capable of piloting the Egg-O-Matic as proficiently as the fat man himself.
General
In Sonic or Tails' stories through Sonic 3 & Knuckles, Eggrobos are first seen during the cutscene at the start of Sky Sanctuary Zone, launching from the Death Egg's equatorial circumference as the great battlestation climbs back into space under the power of the Master Emerald. These rotund badniks are the only foes (bar Mecha Sonic) to be found in Sky Sanctuary.
For Knuckles, however, these badniks play a more integral story role. As the echidna is still unaware that Eggman is the real villain, his boss fights see an Eggrobo piloting the boss machines during every level save Flying Battery Zone.
Eggrobo is also an unlockable character in Sonic R, with stats and abilities similar to those of Eggman's himself. It is unlocked by winning a race against the Eggrobo after collecting all the gold coins in Regal Ruin.
When Eggrobos appeared in the Archie-produced Sonic the Hedgehog comic book, they were referred to as "Eggbots".