- This article is about the Death Egg space station that appeared in Sonic the Hedgehog 4: Episode II. For the Death Egg space station that appeared in Sonic the Fighters, see Death Egg II. For the second Death Egg that appeared in the Archie Comics, see Death Egg Mark 2.
The Death Egg casts a shadow throughout the entire story of Sonic the Hedgehog 4. Though a similar space station appears as the final location of Episode I, the Death Egg makes a comeback in the later half of Sonic the Hedgehog 4: Episode II as the Death Egg mk.II. This new Death Egg appears as a mechanized version of Little Planet—literally, the entire station is built around it. While it retains many characteristics of its predecessor, the Death Egg mk.II is still under construction and still very much incomplete. It can be seen in the Act 3's night background of Sylvania Castle as well as White Park. The Death Egg mk.II is shown to have a fleet of smaller, mass-produced stations which resemble the E.G.G. Station Zone.
After beating Metal Sonic in Sky Fortress Zone, Eggman ditches his damaged airship and decides to retreat to his new space station with Metal Sonic while Sonic and Tails following them in an escape pod. Inside Death Egg mk.II Sonic once again races his doppelganger only this time with Tails by his side. The duo then confronts Robotnik in the heart of the Death Egg, facing his latest creation. Upon being defeated, the new Death Egg begins to suffer massive internal damage and can be seen shutting down in space. Luckily, Sonic and Tails manage to escape at the last moment crashing down to Earth in the doctor's escape pods.
While it is unknown what happen to the Death Egg mk.II afterwards, it can be assumed that without its internal systems to prevent the Little Planet from disappearing again, it was pulled away from the Earth by the Little Planet's natural cycle for then to disappear with it to regions unknown.
The Death Egg Mark 2 debuted in the Archie continuity nearly a year before the games. Though similar, the Archie version differs in size and shape, and was not constructed around the Little Planet.
In this incarnation, it can manipulate time and space by using a Chaos Emerald, and, like its comic predecessor, is equipped with a World Roboticizer.
The Death Egg Mark 2 is Doctor Eggman's main base and ultimate weapon, originally disguised as an egg-shaped bunker. When the station attacked the Freedom Fighter's base, Sonic the Hedgehog and Sally Acorn boarded it and fought against an upgraded Silver Sonic, and another rebuilt Metal Sonic. The Death Egg later retreated after sustaining damage, but not before launching Titan Metal Sonic and Tails Doll into New Mobotropolis. (StH: #224, #225, #230, #231)
- While this Death Egg has constantly changing gravity similar to Sonic & Knuckles Death Egg Zone, there are no enemies present aside from Dr. Eggman and a robotic doppelganger of Sonic (in this case, Metal Sonic), making it highly reminiscent of Sonic the Hedgehog 2's Death Egg Zone.
- In the final showdown with Metal Sonic, not only is the race from Stardust Speedway recreated, but the Stardust Speedway Bad Future music from the Japanese/European soundtrack for Sonic the Hedgehog CD has been remixed. Metal Sonic is even defeated exactly the same way as he was in Sonic the Hedgehog CD.
- Unlike its predecessor, which was made entirely from scratch, this Death Egg is built around the Little Planet from Sonic the Hedgehog CD, which is also a giant spherical structure in bad future.
- This version of the Death Egg is called "mk.II", even though there was already a Death Egg II which Dr. Eggman built in Sonic the Fighters.
- The final boss appears to look like a realistic heart, possibly because it is in the "heart" of the Death Egg mk.II.
- Unlike its predecessor, this Death Egg does not plummet back down to Sonic's world or explode after the final battle. Instead, it remains stationary in orbit and all the lights on the exterior turn off, implying that while its still intact on the outside, the damages made on the inside by Sonic and Tails have caused it to power down for the time being.