This Gyarados is a water/ -type Pokémon owned by Lance.
To survive the fall in the lava, Lance shielded himself with his Gyarados and two of his Dragonair he soon healed. He also had them use Bubble Beam, which became invisible due to the sunlight reflection, to attack Yellow. Giovanni, who saved Yellow, had his Rhyhorn and Nidoqueen use moves that toppled the ground, making the bubbles visible again. Since Nidoqueen failed to attack the bubble made by Lance's Pokémon, Lance had his Gyarados and Dragonair retaliate with Hyper Beam. However, Giovanni dropped his Poké Ball. When Lance was distracted, the Ball opened and Beedrill came out, who used Twineedle to break the formation Gyarados and Dragonair made, allowing Beedrill to intimidate Lance.