Corona is a golden-yellow extraterrestrial resembling a stylized sun, noted for his distinctive head shape. He originates from another planet and crash-lands on Earth in a desert inside a UFO, accompanied by his companion Crescent. A human showgirl named Funny discovers them and adopts both as pets.

During their time on Earth, Corona typically receives more affection and positive attention from Funny compared to Crescent. His personality is emotionally reactive and dependent; he frequently responds to minor inconveniences or perceived slights with loud wails or intense crying.

Narrative instances show Corona demonstrating unexpected capabilities, such as defeating cloud-like entities. A notable moment occurs during the "Cabbage" episode where Corona temporarily participates in nurturing behaviors alongside Funny and Crescent, treating a cabbage like an infant. This represents a shift from his usual self-centered reactions.

The series concludes with Corona and Crescent departing Earth when fellow aliens return for them, despite Funny's initial resistance. This departure resolves their time as pets.