Pibu was created in Playful Porygon2 when his parents, Red's Pika and Yellow's Chuchu, were left in the Day Care after Yellow had stopped there after a run-in with Lugia. The Day Care was later attacked by Masked Man's mind-controlled forces so that he could obtain the Silver and Rainbow Wings and create the GS Ball. To protect their unborn child, Pika and Chuchu escaped to the Ilex Forest, only to be immediately captured by Pryce. Pryce used the two as hostages so that Gold would be forced to surrender and stop chasing after him.
After Gold gave up, Pryce tossed the Pikachu and the Egg away since he no longer had a use for them. Gold managed to catch the three before they fell and was left at the mercy of Pryce's attacks. After Pryce left, Gold learned from Professor Oak that he had a special talent in hatching Pokémon Eggs. Just then, the Egg hatched into a Pichu, a Pokémon no one had seen before. Together, Gold and Pichu followed Pryce into the Crack in Time to stop his evil plans. Although they fought hard, Pryce managed to defeat Gold and Pichu by freezing them in the time stream, which had the effect of trapping them in a thin sheet of ice. After being rescued by their friends, Gold and Pichu jumped into the Ilex Forest shrine once again to stop Pryce from using Celebi to go back in time. With electricity absorbed from Raikou, Pichu destroyed the GS Ball and freed Celebi with an attack Gold dubbed "Super Rising Thunder". With Pryce defeated, Pichu, Gold, and their friends were safely returned to the real world. There, Pichu was reunited with his parents and given the nickname "Pibu" by Yellow.
In PSs1, Gold and Red go to train on Mt. Silver, with Pibu being trained by his father. However, he was quickly kidnapped by a wild Venusaur and Poliwrath, who injured Gold, forcing Red and Pika to get Pibu back alone. After a brief struggle, Pika defeated the two Pokémon and rescued his son. Later, the group rested at Red's house, where Red revealed that the Super Rising Thunder technique that Pibu used to defeat Pryce was actually the move Volt Tackle. Red then lent Gold his electricity-insulating gloves so that he and Pibu could practice using Volt Tackle.
Pibu appeared in a fantasy in Secrets from Sneasel, where Yellow talks to Chuchu about reuniting with Pika.
In The Final Battle VII, Pibu fought in the final battle against Guile Hideout. He was first sent out to hand Emerald the soil from Faraway Island and then went to join his parents out in the sea. After the combined efforts of the Pokédex holders' ultimate moves failed to defeat Guile's monster Kyogre, Pibu, Pika, and Chuchu finished the creature off with a triple Volt Tackle. After the final battle had ended, Pibu was seen playing with Anabel's Raikou.
In All About Arceus VIII, Pibu helped Celebi gather herbs to make medicine to cure Giovanni's disease while he was off helping Gold, Silver, and Crystal at the Sinjoh Ruins. He is assisted by the Spiky-eared Pichu, and they meet the Team Rocket Elite Trio, who were guarding the forest under Giovanni's command. When a group of Team Rocket Grunts put the Elite Trio under the pretense that they are traitors, they accidentally trample over the two Pichu. Angered, Pibu and the Spiky-eared Pichu attack the Grunts by shocking them. This allows the Elite Trio to get away fast enough so that they can hand the herbs to Giovanni and heal his disease. When Pibu returns to Gold, he blushes when Gold points out that he brought a girl Pichu home with him.