Koga had Golbat attack Blue, who was lying immobilized on the floor. Red sent Poliwrath to intercept the attack, so Golbat attacked Poliwrath instead. After Red was restrained by Grimer, Golbat went to attack Blue, who sent Pidgeot to attack Koga. After Koga was defeated, Blue took Golbat and had it show where his grandfather was located. Through Golbat, Blue found Professor Oak at the basement of Silph Co.
After meeting up with Koga and going to battle against the Elite Four, Blue returned Golbat back to Koga. Koga had his Golbat use Supersonic to trace the Elite Four. Soon, they were attacked by Agatha, whose Arbok used Leer. To counter these effects, Golbat used Haze. Just then, stalactites from the cave started to fall down; Blue rescued Golbat, but the two were separated from Koga. As Gengar used Lick on Blue, he became blind and relied on Koga's Golbat to move around. However, even this was countered, as Agatha's Golbat went to attack Blue.
To help Blue, Koga threw shurikens, which contained Poké Balls. One of them, containing Koga's Ekans that carried Parlyz Heal, was sent to Blue. Blue was healed and managed to defeat Agatha's Golbat, while Koga's Golbat returned to its master to help him. In a tight situation, Koga had his Golbat use Leech Life on Koga's arm. Golbat sucked the blood and spit it on Agatha's Arbok, who was unable to change its color pattern for the battle. Since Agatha continued to fight with her Gengar, Blue had Golbat use Confuse Ray to illuminate the cave, revealing Gengar's position. After Agatha escaped, the cave started to crack; Koga took Golbat and had Muk extend itself to protect both of them. Eventually, Koga and his Pokémon survived and escaped Cerise Island and met up with Bruno.