Gaa-chan is a yellow duck-like figure and the best friend and constant companion to Baja within an animation studio setting. Originally an inanimate object, Gaa-chan comes to life through the narrative, sharing daily adventures and activities with Baja. Their interactions form a central part of the story, showcasing a close bond as they explore the studio together.

Guided by the fairy Coco, Gaa-chan participates in magical experiences alongside Baja. After hearing director Kanako express her wish to visit the sea, they use magic to fulfill their curiosity about the ocean, leading to shared imaginative sequences where they collectively experience the sea through magical means.

Gaa-chan's physical representation includes a distinctive pose gently holding Baja's tail, emphasizing their inseparable friendship—a dynamic reinforced through merchandise depicting them together in this characteristic interaction. Gaa-chan's background, character development, and role remain confined to these interactions within the original OVA across all available official media.