Great North Gem Monsters

The Great North Gem Monsters are two Corrupted Gems that are antagonists in the Cartoon Network show Steven Universe. These two Gem Monsters made their appearance in the episode, "Gem Hunt", where they are encountered by Steven, Connie, and Pearl during their journey in the Great North. Jasper gathered these two Gem Monsters to attack the Crystal Gems.

Aquamarine Gem Monster
This gem monster has three short horns and is aqua green with red lines and light pink spots. It's gem is also on it's chest. In "Gem Hunt", it is encountered alongside the Orange Gem Monster, and Steven and Connie find it cornered at the bottom of a cliff. After Pearl talks loudly on the Cookie Cat walkie talkie, the monster directs it's attention to Steven and Connie and attempts to kill them, but Jasper poofs the gem before it could do so and walks away with both it's and the Orange Monster's gem after she gloats at Steven. In "Crack the Whip", Jasper uses the Aquamarine Gem Monster as a steed to fight Steven and Connie, who fuse into Stevonnie during the fight. After the Aquamarine Gem Monster is poofed again, Jasper takes it's gem and retreats to the bottom of the ocean, intending to come back for revenge.

Orange Gem Monster
This gem monster has three horns each and is colored orange and brown. Just like the Aquamarine Gem Monster, the Orange Monster's gem is also in it's chest. It appears in "Gem Hunt" alongside the Aquamarine Gem Monster, however, it retreats with the Aquamarine Gem Monster before it can fight Steven, Connie, and Pearl. It was then shown to be poofed by Jasper off-screen after she poofs the Aquamarine Gem Monster. In "Crack the Whip", it emerges from the water of Beach City and it scares Sour Cream away. Amethyst eventually ties the creature with her whip and poofs it's gem, which Steven bubbles and sends back to the Burning Room with the other Corrupted Gems.

Trivia

 * These gems are speculated to be Ocean Jasper and Biggs Jasper. They are also speculated to be Bloodstone and Desert Jasper.