|“||"Want form! WANT FORM!"||„|
The Cluster is the name of a massive gem monster and is mentioned in Steven Universe. It is a giant Cluster Gem that is currently incubating deep beneath the Earth's core and is said to be larger than the Earth itself and it will destroy the planet once it reaches its final form. The Crystal Gems were working to stop The Cluster from reaching its final form, which they eventually succeeded in doing.
The Cluster serves as the main antagonist for the second half of Season 2 and the beginning of Season 3.
The Cluster is first mention in the season one episode Jail Break where Peridot arrives on Earth with her escort Jasper and her informant Lapis Lazuli. Peridot looks at her objectives and she is sent in to investigate and check up on The Cluster.
The Cluster is mentioned again in Catch and Release and is explored in greater detail.
In When It Rains, after Peridot is able to form some sort've truce with the Crystak Gems, she is freed by Steven and she takes him to the Kindergarten where she brings up the monitor and she shows Steven a map of the Earth and the location of where The Cluster is at. Peridot then reveals to Steven that once The Cluster is finished incubating, it will grow to become larger than the Earth itself and it'll destroy the entire planet. Peridot then reveals that once The Homeworld saw Earth as no longer a viable colony to mass-incubate gem warriors, the homeworld had began experiments involving the forced fusion of Gemshards to create some kind of "Gem Geo-Weapon".
She then reveals in the Prime Kindergarten Control Room that the Gemfusions they Crystal Gems had fought before, were actually prototypes for The Cluster and reveals it to be a massive giant comprised of millions of gemshards and once it reaches its final form, it will grow to become bigger than the Earth and the whole planet will be destroyed if it's not stopped.
Ever since Back to the Barn, the Crystal Gems and Peridot have been working together in an effort to stop The Cluster before it can reach its final form and destroy the Earth. The gems are currently trying to build a drill so they can make it to the Earth's core and stop The Cluster from incubating.
It's revealed by Peridot in It Could've Been Great that the Homeworld's intention with the Cluster was indeed to incubate the time enough to remerge from earth's core and destroy it in the process. Later on, Steven and the Gems travel to the moon and learn about the Cluster's coordinates thanks to the control panel of the base. However, it also revealed the Cluster is 2,500 units down earth.
The Cluster finally starts to free itself in Super Watermelon Island creating earthquakes on Mask Island where Steven, the Crystal Gems, Malachite and the Watermelon people were. After defeating Malachite and unfusing back to Jasper and Lapis Lazuli, the Cluster rumbles from the underground making quakes everywhere, one of them taking Jasper's unconscious body while Lapis is saved. Garnet tells to Steven (Who was possessing a Watermelon on his sleep) to wake up and hurry up with the drill before it's too late.
In Gem Drill, Steven and Peridot set to travel underground using the drill. As Steven and Peridot proceed, they encounter several Cluster Gems on their way coming from the Cluster, but they get rid of them easily. At one point, Steven came up with the idea of bubbling all the Cluster's gems but Peridot sadly explains there is no way to help them, because they are now million of shards united without any memory of what happened save for having one common goal, getting enough of their lost gem shards to form. Afterwards they finally arrive at the Cluster, Steven suggests they can help them but Peridot tells him destroying it is the only way to save earth.
The drill is activated but as it works, the drill eventually loses three heads and fails to keep drilling, making Steven fall unconscious. When Steven wakes up, he finds himself inside the Cluster, he tries to convince them that they don't need to form when they can find more gem shards just where they are, and what they need is company, considering the fact that if they form back it will be the destruction of the whole planet and the gem shards they can find. Steven wakes up and tells Peridot the Cluster no longer wants to form back and needs to be bubbled, though at first they didn't seem to know how to do it, the Cluster's Gems start to bubble each other. Steven helps to unite all the gem shards with the Cluster, becoming all one in a giant bubble. Steven and Peridot return back to the barn where the Crystal Gems have returned with a unconscious Lapis. Steven announces the Cluster now is completely bubbled and doesn't need to form to achieve its goal. The final scene consists in the Cluster peacefully resting in Earth's core.