Baby Panda, also known as Panny or Pan-chan, is the young panda cub companion to Mimiko and the biological child of Papa Panda. He possesses a small, rotund body with soft panda features, including large black eye patches and a playful, childlike nature.

Panny exhibits energetic curiosity, often exploring independently despite Mimiko's instructions. This leads him to dart after Mimiko to school, sparking chaotic chases by other children. His playfulness includes rolling down hills during walks, sometimes unintentionally separating him from Mimiko and Papa Panda. While generally cheerful, Panny shows flashes of timidity, like initially recoiling from unfamiliar creatures such as the baby tiger Tiny.

His family dynamic is unconventional yet devoted. After encountering Mimiko alone at her home, Panny and Papa Panda form an adoptive family unit with her. Panny embraces Mimiko as a maternal figure while Papa Panda acts as a paternal figure for Mimiko. This structure highlights mutual care, with Panny relying on Mimiko for daily routines like meals and bedtime.

Within the Rainy Day Circus narrative, Panny discovers Tiny the tiger cub in his bed during a Goldilocks-inspired moment, demonstrating his inquisitiveness. He bonds with Tiny through shared play, including circus-inspired activities like ball-balancing. During a flood crisis, Panny assists Mimiko and Papa Panda in rescuing circus animals from a stranded train. His playful interaction with Tiny unwittingly restarts the train, requiring Papa Panda's intervention to avert disaster.

Panny shows quietly evolving capabilities across events. Initially needing close supervision, he gradually participates in cooperative efforts like distributing food during floods or helping rescue animals. His musical side emerges through trumpet playing during celebratory family parades.