The Cluster is a massive Cluster Gem. It is composed of millions of gem shards and, in its emerged form, would be larger than the Earth. It assisted Steven in bubbling itself in and now remains dormant in the Earth's mantle.
Powers and Stats
Tier: At least 5-B | At least 5-A
Name: The Cluster
Origin: Steven Universe
Classification: Forced Gem Fusion
Powers and Abilities: Superhuman Durability, Can cause earthquakes, Can go into it's physical form, which would destroy the planet it is in. | Superhuman Physical Characteristics, Immortality (Type 1), Bubble Manipulation, Possible Shapeshifting, Fusion (Only with other gems), Possible Regeneration (Likely Low-High), Immunity to Gravity Manipulation
Speed: None (Can't move) | Unknown (Featless), Possibly Massively Hypersonic due to it's size
Lifting Strength: None | At least Class Y due to it's size
Striking Strength: None, At least Class XJ via taking form | Class XMJ via sherr size
Stamina: Likely Limitless (Gems can "get all the energy they need from their gems")
Standard Equipment: None | Unknown
Weaknesses: Can't take form without destroying the planet, can't stop taking form after the process starts, can't think straight, has millions of disturbed minds screaming in pain inside it's head.
Key: Gem Form | Physical Form