The Death Egg is a space station in Jacknjellify's Sonic The Hedgehog. It is the first and most famous of Eggman's space stations. Hosting some of the doctor's most deadly creations of all time, this vast stronghold serves as the scientist's ultimate weapon and key component in his various quests for world dominance.
It is a massive orbital fortress and space station.
However, the Death Egg is not a planet.