Melonpanna originates from melon bread baked by Uncle Jam using the nectar of love's flower. Her physical composition requires melon juice to prevent energy depletion. She possesses large green eyes, a small green nose, and three diagonal facial lines. Her consistent attire features a dark green uniform with a cursive "m" insignia, light green accessories, and a dual-toned cape—green exterior and orange interior.

Kind and gentle by nature, she avoids conflict but fights when necessary. She regards Anpanman as an older brother and maintains a close, sisterly bond with Creampanda. Her deepest emotional connection is with Rollpanna, her older sister; separation from Rollpanna often triggers loneliness.

Her abilities include flight via her cape and signature techniques: The Melo-Melo Punch inflicts temporary affectionate paralysis or awakens deeply sleeping individuals, while Melo-Melo Juice drawn from her head reverses Baikinman's "blackening" effects on allies. This juice weakens if Rollpanna's goodness diminishes. She also wields superhuman strength, typically reserved for defense.

Within *Inochi no Hoshi no Dolly*, Melonpanna participates in the Star Festival events involving Dolly—a doll animated by a Star of Life. She fulfills her standard heroic role during Baikinman's giant robot conflict. Her portrayal aligns with her franchise depiction, supporting ensemble actions without unique narrative focus.

Across official media iterations, Melonpanna's foundational traits, relationships, and capabilities remain consistent, lacking significant evolution or permanent alterations.