Kuuta is a small white monkey with blue eyes, a small round tail, and a yellow handkerchief worn around the neck. Owned by Natsumi, the granddaughter of the Professor, he was given to her at a very young age and grew up alongside her, forming an inseparable bond.

His personality is laid-back, carefree, and highly friendly toward both humans and other monkeys. Though not very intelligent, he displays a strong sense of curiosity and innocence. Kuuta enjoys bananas, looking at reflections, playing at the Big Banana in the Park, and wandering off. He dislikes Natsumi being upset, the Neo Pipotrons, and Specter.

During a stormy night at the laboratory in the first season, Kuuta mysteriously disappears. Through the actions of Pipotron J, he dons a Peak Point Helmet that forcibly transforms him into Specter. Natsumi initially believes Kuuta ran away. The AI assistant Casi later confirms that Specter and Kuuta are the same entity. Specter initially resists reverting but is moved after witnessing the protagonists' kindness toward monkeys. He transforms back into Kuuta after saving Kakeru from Pipotron J and removing the helmet.

The second season reveals that Kuuta served only as a vessel for the true Specter, who emerges as a separate being with full powers. Throughout this season, Kuuta remains himself and does not transform again.

In terms of abilities, he possesses typical monkey traits such as climbing trees, though he is not very strong and is prone to injury.

His allies include Natsumi, the Professor, Kakeru, Hiroki, and Casi. His enemies are Specter and the Neo Pipotrons.