Larimar

Larimar, also known as the Ice Monster when corrupted, was a corrupted Gem that first appeared in "Monster Buddies". She was healed along with the other corrupted gems in "Change Your Mind".

Appearance
She possesses a bulky body that is colored varying icy shades of blue. The creature also possesses two, very large arms with four spiky fingers each and two short legs. Her head is carved into five sharp protrusions. She has two dark, hexagonal eyes and a gaping, dark mouth lined with sharp teeth. This monster is slightly taller than Garnet.

Despite this, however, when she is uncorrupted, she is quite small in size.

Thousands of Years Ago
Larimar fought in the Rebellion on Earth and was unable to escape the Diamonds' Corrupting Light, mutating into a Corrupted Gem upon exposure to the light. In her corrupted state, she found refuge in an ice cavern.

"Monster Buddies"
The Crystal Gems are shown fighting Larimar in the large cavern inside a snowy mountain. She's shown to be preventing them from acquiring a powerful, elemental artifact called the Shooting Star. After her arm falls off, Garnet deals the final blow on her, thus, defeating Larimar. Pearl bubbles her gem and transports it back to the Burning Room. Her gem is seen again when Garnet bubbles Steven to the Burning Room and is later seen again when Steven bubbles the Centipeetle Mother's gemstone to the room along with the "Chaaaaps".

Steven Universe: The Movie
Larimar, presumably uncorrupted during the events of "Change Your Mind", appears as a resident of Little Homeworld.

Trivia

 * Larimar, as well as a stronger version of her, appear as antagonists in the flash game, "Sword Dancers".
 * In her corrupted form, she bears a resemblance to the Freezies from the Super Mario series, except she has arms and legs.

Gemstone
Monstruo de Hielo Lodowy Potwór pt-br: Monstro de Gelo Ледяной монстр