The Egg Cerberus is a giant, armoured robot dog created by Dr. Eggman. it is the first boss for Sonic and Shadow in Sonic the Hedgehog (2006).
The gigantic Egg Cerberus is heavily armoured and attacks simply by charging around its combat area, trampling everything in its path. It is too big and too strong for Sonic to damage on his own, but he is able to grind up on the dog's tail and upper back and grab onto the antenna on its head. Doing this will interfere with Eggman's remote control signal and the dog will charge about in a frenzy. If the player pushes or pulls the antenna, he can coerce the Egg Cerberus to run into walls and obstacles. The dog will take more damage depending on the strength and weight of the obstacle it rams. When Sonic battles the Egg Cerberus in the ancient Soleanna coliseum, running into stone pillars will only do minor damage, whereas running into the arena wall will take off a quarter of the dog's health, and ramming one of the two statues at either end of the arena will take off half its health. The Egg Cerberus loses its head armour when it drops to half health.