The Alien Egg is a green-striped egg found on Mars by Apple in Marsh on Mars. Once the challenge ends, Fan decides to foster the egg.
In The Series
The Alien Egg was originally discovered on Mars in Marsh on Mars, mistakenly interpreted as Marshmallow by Apple. Apple then takes the egg back to the island, where she discovers that Marshmallow is safe. MePhone4 questions The Bright Lights where they got the egg, but immediately disregards it. Despite MePad's warning, Fan announces that he will keep the egg for company.
The egg is not seen again until Cooking for the Grater Good, where Lightbulb attempts to break it open to use as protein for her pizza, although Fan quickly snatches the egg back from her.