Pichu is a small, ground-dwelling rodent Pokémon with pale yellow fur. Its eartips, collar, and tail are black and angular. Pichu's pink cheek pouches can store small amounts of electricity, and its tiny nose looks like a dot. Pichu is classified as a quadruped, but it can walk easily on its hind legs.
Pichu is a social Pokémon known for its playful and mischievous demeanor. It is usually found in groups and often touch tails with other Pichu as a show of courage, creating a shower of sparks that can make them cry. It is inept at storing electricity, and may discharge if amused, startled, or subjected to shock. However, it cannot discharge without being shocked itself. Charging up is more easily done on days of dryness or with thunderclouds. The crackling of static electricity generated by Pichu is audible. It can zap an adult human, but will surprise itself if it does. Pichu primarily lives in the forest, though it has also been depicted to thrive in urban areas.
Ash's Pikachu was revealed to have been born as and evolved from a Pichu in Enter Pikachu!.
Pichu made its main series debut in The Apple Corp, where they were stealing apples from Charmaine's apple orchard. In the end, Charmaine decided to keep all of them so they could help around the orchard.
In Pokémon Mystery Dungeon: Team Go-Getters Out of the Gate!. Pichu's big brother Pikachu was lost and he was so worried, that he went out to find him. Pichu came across Team Meanies, but they played a trick on Pichu when he asked for their help. Pichu found Team Go-Getters, who gladly let him come along with them. Pichu was eventually kidnapped by the Skarmory that had kidnapped Pikachu.
Two Pichu six Wynaut and a Buizel were forced off their island in Pikachu's Island Adventure by Meowth and his cronies, who claimed the island for themselves. As a result, Pikachu and his friends agreed to help them reclaim the island.
Sho owned a Pichu in Pika and Goliath!, as he sought to have possession of one Pokémon each from the Pikachu evolutionary line. Arrogant like its Trainer, it would watch both of Sho and his Raichu's battles with Ash.
A Pichu in A Jolting Switcheroo! belonged Lena, but was in Lyn’s care. Lyn's bag was accidentally taken by Bonnie, whose similar bag had her Dedenne inside; they eventually got their bags and Pokémon back.
Pichu, the Tiny Mouse Pokémon. A pre-evolved form of Pikachu. Despite their size, Pichu release bursts of electricity that can shock even humans. However, Pichu are unskilled at controlling their electricity, and sometimes release it by accident when surprised, or when laughing, and shock themselves.
Pokémon Stadium 2: Pichu stars in the mini-game "Pichu's Powerplant." Similar to Pikachu's and Voltorb's mini-game, "Thundering Dynamo", in Pokémon Stadium. The player has to be the first to charge up the most electrical power in order to win.