Pichu Little is the younger sibling in a pair of Pichu brothers, slightly smaller than his older brother, Pichu Big, and lacking Pichu Big's distinguishing tuft of hair. Both share the typical Pichu appearance: small yellow rodent-like bodies, large ears, and electric bolt-shaped tails.

Energetic and mischievous, Pichu Little often engages in playful antics that cause trouble, like attempting to steal balloons or provoking a Houndour, frequently leading to chases through their home of Big Town. Despite this, he shows loyalty and willingness to help, such as guiding a lost Pikachu back to his trainer after initially causing the separation. His relationship with Pichu Big involves frequent arguments, sometimes escalating into shoving matches or quarrels. However, these disputes are short-lived, and the brothers always reconcile quickly, highlighting their inseparable bond.

Pichu Little and Pichu Big lead the Pichu Posse, a group including Wooper, Magby, Teddiursa, and Azumarill. They explore urban environments, turning ordinary settings into chaotic playgrounds. In one incident, Pichu Little spots balloons and convinces Upah to steal them, resulting in Pichu Little being carried away and needing rescue. Such scenarios typically require collaborative efforts to resolve the chaos, like stabilizing a collapsing structure or retrieving scattered party invitations.

Their story includes rebuilding their damaged secret base after an attack by Houndour, demonstrating resilience and teamwork. The brothers also appear in other media, like the game *Pokémon Channel* where they search for misplaced party invitations. Cameos in anime openings and endings, such as the Japanese credits for *Pokémon: The Rise of Darkrai* and *Meloetta's Moonlight Serenade*, establish them as recurring background figures.