The Death Egg Robot is the final boss of Sonic the Hedgehog 4: Episode I. It is the upgrade of the original Death Egg Robot, featuring a slight redesign and new color scheme. It is fought with Sonic the Hedgehog directly after defeating the Flying Egg onboard the E.G.G. Station Zone.
When the battle begins, the Death Egg Robot first repeats its pattern, as moving slowly, tries to fall down on player's neck and fire its arms. It does not include small bombs when the player is behind of it. It is, in essence, the same mech from Sonic the Hedgehog 2, but like the other bosses in the game, it shows new attack patterns after being heavily damaged.
After sixteen hits the Death Egg Robot becomes surrounded by electricity, making it impossible to damage directly. It also appears to malfunction, randomly leaping across the field both forward and backward, firing its rocket hands at a much faster pace. To damage the Death Egg Robot, Sonic must knock its severed arms back into it when one flies off and floats back down. This disables its electrical field long enough to strike its body. After about six hits, the Death Egg Robot starts shooting lasers at Sonic from a compartment in its head. There are two types of lasers, the first being pink bullets commonly used by many other enemies within the levels and second a powerful beam that shoots along the ground (this attack is absent from the iOS versions).
On its last hit, the Death Egg Robot will fly up and attempt to destroy the space station around it to drop Sonic into the vacuum of space. It must be hit before the floor falls apart to clear the game. If the player does not hit the Death Egg Robot in time, it will break the floor causing the player to fall and lose a life.
- The Death Egg Robot's final attempt to defeat Sonic the Hedgehog is similar to the Egg Viper's last attempt to defeat Sonic in Sonic Adventure.
- The alarm sound used when Death Egg Robot is performing its final strike is similar to the alarm noise used in Sonic Adventure 2.