Despite its name, Egg Turtle bears a closer resemblance to a plesiosaur. It has a white part on its head, which is where the Egg Mobile is located. Its color scheme varies depending on the chosen character:
Sonic: Egg Turtle's flippers, shell and spikes are green. The spikes on its shell have yellow tips. Most of its body is gray, while its underside, neck, and the rotor on its back is red.
Blaze: Egg Turtle's flippers, shell and spikes are purple. The spikes on its shell have pink tips. Most of its body is gray, while its underside, neck, and the rotor on its back is cyan.
The Egg Turtle chases Sonic/Blaze around the water-covered ring until it gets close enough to slam its body (or sometimes its head) into them. If this attack is successfully avoided, Egg Turtle moves to the center of the ring, targets Sonic/Blaze and smashes its head at them, leaving it vulnerable and open to attack. As the battle proceeds, the water drains to the point where Sonic/Blaze are standing on dry land. At this point, the Egg Turtle extends its neck, attempting to bite Sonic/Blaze. If successful, its neck quickly retracts back into its body, but if it misses, Sonic/Blaze can easily damage it. The Egg Turtle is defeated after it has been hit six/eight times.
It should be noted that even though the majority of the fight takes place underwater, Sonic/Blaze will not drown.