As its name implies, Egg Scarab is based on a scarab or a dung beetle. An Egg Mobile is located in the white part of its head. Its color scheme depends on the character the player has chosen:
Sonic: It is mostly gray with blue parts on the arm shields, leg shields, and lower torso. It has black spikes, and yellow arms and legs. The giant spiked ball is mostly gray with thin black lines.
Blaze: The upper torso and the stripes on its claws are purple. It has a red lower torso and claws, as well as gray and yellow under the torso and arms. The spiked ball is mostly gray with thin black lines.
The battle takes place in a circular arena, in which Egg Scarab chases Sonic/Blaze rolling its spiked ball around the area until it pushes the ball towards Sonic/Blaze. When the ball is close to the player, he/she must hit it to deflect the ball while it is not covered in spikes to hit the Egg Scarab from behind (Egg Scarab turns around when the spiked ball is close enough to it). If the player hits the spiked ball too soon, the Egg Scarab will simply catch it with its claws. At times, Egg Scarab will fly to the middle of the circle to throw multiple spiked balls at the player. Once the battle progresses to a certain point (when the player hits the Egg Scarab about five-seven times), Egg Scarab will jump over the spiked ball to avoid being hit and the player must hit the ball again. Once hit six or eight times, Egg Scarab is defeated.
This is only non-final boss that both Sonic and Blaze fight at the same time.