This Gorebyss is a water-type Pokémon owned by Amber.
Amber faced some fiery illusions and had Gorebyss wash them away. Amber knew it was Blaise's doing. Blaise tried to propose Amber to join him. Amber refused and Gorebyss used the power of sea to conjure Hydro Pump, which hit Blaise and Slugma.
After accepting the request to join him, Amber and Blaise, along with their Pokémon, found Hoopa, who could summon Kyogre and Groudon. During the night, Gorebyss sprayed water on Hoopa, which infuriated it. Hoopa conjured a ring, though it saw Blaise's Slugma's illusions of Kyogre and Groudon, which Hoopa eventually summoned. Ruby and Emerald found Amber and Blaise, who provoked Hoopa. They started to attack their Gorebyss and Slugma with Ruby's Milotic, Feefee, and Emerald's Dusclops. Blaise's Slugma conjured illusions and made Ruby and Emerald devastated by the illusions.