Kogoro

(556) A human-like alien and space detective who is a childhood friend of Keroro. He isn't very good at his job, and instead lives in a cheap apartment on a shoestring budget. Kogoro seems to grin and laugh all the time, regardless of his actual feelings. His hobbies include collecting colored boxes. His appearance and mannerisms are a parody of Kenji Ooba, the star of the tokusatsu series Space Sheriff Gavan.

(Source: Wikipedia)