Bananya is a small cat residing inside a banana, representing a newly discovered species of tiny cats inhabiting bananas. These creatures emerge only when humans are absent, instinctively concealing themselves by posing as ordinary bananas when people are near. The species blends feline behavior with banana-like qualities. Bananya communicates through vocalizations primarily consisting of variations of "nya," characteristic of the species' limited speech. Physically, Bananya possesses rosy cheeks and a mischievous demeanor.

Originating from another planet, Bananyas live covertly within human households on Earth. Bananya's lifelong aspiration is to bathe in chocolate and become a chocolate-covered banana. During various adventures, Bananya interacts with multiple members of the species, including Tabby Bananya, Black Bananya, Long-haired Bananya, Bananyako, Daddy Bananya, and Baby Bananya. Relationships involve unrequited affections, such as Tabby Bananya's admiration for Bananyako, who favors Long-haired Bananya.

In the third season, Bananya gains a new companion, Baby Sweet, a floating kitten Bananya distinguished by a bib-like section of its peel. Baby Sweet possesses spontaneous, unpredictable teleportation abilities that require recharge time indicated by a paw print on the bib. This ability transports Bananya and Baby Sweet to diverse global locations, historical periods, and thematic environments. Their journeys introduce new characters, including Manul Bananya (a Pallas's cat variant), Western Bananya, Vampire Bananya, and Banawan—a dog-banana hybrid confirming expanded lore.

Throughout these experiences, Bananya maintains core traits while navigating episodic scenarios across varied settings, such as haunted mansions, whodunit mysteries on trains, and encounters with culturally themed Bananya variants like Namaste Bananya (associated with Indian motifs and curry) or Elizabeth Bananya (characterized by refined manners and tea-drinking). Earlier episodes established behavioral patterns, like Bananya's instinctual pursuit of a mouse despite attempts at friendship, emphasizing the species' biological duality balancing feline impulses with banana-related themes.