- "This is where it began, and this is where it ends. For all of us."
- —Melanie during Pauline's vision in the tunnel vortex.
The Egg, was first discovered during a summer night in 1988, in a meteor crash site. Which was found in a woods near Chester's Mill, by four teenagers Sam, Lyle, Pauline and Melanie (the original "four hands"). In the process Melanie dies, scared and confused they covered her death, and left site forgotten.
Six days after the Dome appeared, the Egg is rediscovered by Joe and Norrie, at the center of the dome, with a second mini-dome surrounding it. The next day Joe then tells Julia about the mini-dome, who sees a vision that "The monarch will be crowned." That night Joe move the mini-dome\Egg from the woods to his barn to hide and safeguard it (but he doesn't remember doing so), where the mini-dome reveals four handprint, and Joe, Norrie Junior and Angie realized they are connected to the dome somehow (The "four hands").
Later the mini-Dome dissipates, Julia is anointed as the "monarch" and learn the dome is there "to protect them" from something. Then Julia seeking to safeguard the Egg from Big Jim and others, drops it into the lake, which cause pink to rise from the lake, causing the black curtain that covered the Dome (since Big blackmail?) to be replaced with piercing bright light.
Few days later, the egg was recovered from the bottom of the lake, by the four hands. Then at Joe house, it start to glow to their touch and release pink stars that form the outline of an obelisk, which Junior recognizes from his dream and Melanie says that it's from her home town of Zenith. The scene repeated, the next day in the newly discovered\formed tunnel in the school basement.. (which leads to Zenith, and from there the way goes back into the lake).
Few days later, when Big Jim decide to turn over the egg to the outside, Junior and Melanie decide to keep it safe, by hiding it under his nose, in his underground bunker. The next day, the egg starts to glow and vibrate, emitting high pitched sounds which affects Pauline above, leading her to draw one of her visions. Big Jim finds the egg, when he tries to pick it up, he is zapped clear across the room. Later Joe and Norrie arrive and the egg "calms down". Big Jim wakes up and force them to take it the tunnel under the Chester's Mill School, where he drops it into the chasm, and an earthquake hit Chester's Mill, Pauline visions stop and Melanie Becomes ill.
In episode Black Ice after being thrown into the chasm, the egg appears in Zenith's. Don's team examines the egg that has appeared in the middle of the playground. When a scientist picks it up using a pair of tongs, the egg turns white and rings, and then releases a burst of energy blasting the scientist back.
In episode Turn after discovering that the only way to save Barbie and Melanie is to bring back the egg to the Dome, Don goes to the Zenith playground where he's able to pick up the egg without it causing him any harm. But as he tries to leave with the egg Don is stopped by Malick and his mercenaries.
In episode But I'm Not Don Barbara brings back the egg back to the Dome. There Melanie meets him, then kills him and takes the egg with her. Later Melanie brings the egg to the cacoon cave where she puts it on the main cacoon. In the end Big Jim comes to the caves and with a positive nod from Julia, breaks it.
The egg is a little bit smaller than an ostrich egg in size and is completely black, but on certain occasions it glows in various colors. At close inspection, it seems to be made of obsidian or a similar material. Initially, the egg was surrounded by a protective mini-dome, which can only be touched only by few chosen colloquially referred to as the "four hands" (Joe McAlister, Norrie, Junior, Angie). If anyone else try to touched it, they would be shocked by electricity.
The Egg and the mini-dome are linked and it's believed to be the energy source for the dome.
- Joe theorizes that the mini dome egg could be the dome's energy source. It is what the military and the Aktaion energy company believe.
- In Curtains, when a monarch butterfly starts to smash into the mini-dome and leaving black patches, the same thing happens to the larger dome. When Julia drops the Egg into lake, it causes the Dome to become completely white.
- It's revealed in Alaska that the egg is indeed the power source of the Dome.
- In Caged it's revealed that the egg created the Dome after Christine Price's interaction with it.
The Egg shows the ability to create apparitions of people that tell strange prophetic things and also can be used as a communication link with owners of the egg and the Dome. The big Dome has this ability too but it created apparitions do not speak and only appear on the surface of the Dome.
- The egg first showed Norrie her mother Alice, who died soon after.
- In Thicker Than Water, when Julia touches the mini-dome ,the egg shows the apparition of Joe McAlister which says the phrase "The Monarch will be crowned".
- In the Season 1 finale Curtains, when Norrie touches the mini-dome, the Alice apparition appears again.
Throughout the series, the egg is shown to be concetrating some sort of energy in the shape of pink stars rising up the egg. It can also enduce seizures to the fourth hands in which they repeat cryptic words.
- Joe, Norrie and Angie experience seizures repeating the phrase, "The pink stars are falling". They appear to be the same stars that appear in Junior's mother dreams and are foreshadow both the pink stars on the egg and the events of Ejecta.
- When Joe tried to record the seizures, the Egg warns Joe and Norrie to keep the egg between themselves and other seizure sufferers.
- After the egg was recovered from the lake, it shows pink stars falling in lines, which took shape of a monolith which Melanie confirms is from her hometown Zenith. Later she sees vision of Zenith again, in the tunnel beneath school.
- In Redux, it's revealed that the egg's purpose is to transmit and share that life energy to people.
The Egg is also able to emit a high-pitched noise as well as releasing a burst of electric energy, blasting those trying to touch it. The mini-dome protecting the egg shares this ability too.
- In Let the Games Begin, when Dodee Weaver touches the mini-dome, she is shocked and forcefully pushed away.
- In The Fall, the egg blasts away Big Jim with an energy surge after he finds it and tries to pick it up.
- In Zenith, when a scientist tries to examine the egg, trying to pick it up using a pair of tongs, the egg turned white and ringed, releasing a burst of energy which blasted the scientist.
The egg is also presumed to be able to take control of weather under the Dome  and could be the cause of all strange events that happen under it (strange weather changes, apparitions).
- In The Fourth Hand, it's shown that the mini-dome can be unlocked but only if the four hands of the chosen ones (Joe, Norrie, "Junior" and Angie) are placed on it.
Melanie Cross is shown to have a deep connection to the egg to an extent that she even would sacrifice her life to protect it. She is presumed to be the first protector, as she was the first human to touch the egg.
- When the egg is thrown into the chasm, Melanie immediately faints and becomes ill.
- When scientists in Zenith try to pick it up, Melanie experiences seizures.
In But I'm Not, it's revealed that there were multiple meteorites with eggs inside of them found all over the world. Only the one found in the Alaska and the one in Chester's Mill were intact and only Chester's Mill egg seemed to be functional.
- In episode Legacy it's shown that each individual egg has different characteristics to each other. For example egg found in Alaska was shown to be emitting blue energy and blue stars instead of purple ones shown in Chester's Mill egg.
- Also only Chester's Mill egg seems to be able to create Dome as Alaska one only shared life energy.
- In the series finale it's revealed that there is a new egg in Omaha.
- ↑ Season 2, Revelation
- ↑ Season 1, "Imperfect Circles"
- ↑ Season 1, "Thicker Than Water"
- ↑ 4.0 4.1 Season 1, "The Fourth Hand"
- ↑ Season 1, "Let the Games Begin"
- ↑ Season 1, "Curtains"
- ↑ 7.0 7.1 Season 2, In the Dark
- ↑ 8.0 8.1 Season 2, Going Home
- ↑ Season 2, The Red Door
- ↑ Season 2, The Fall
- ↑ Imperfect Circles
- ↑ Season 1, "Exigent Circumstances"
- ↑ Season 2, Black Ice
- ↑ Speak of the Devil