Spirou's Twin is a human man.
Behind the scenesEdit
Spirou's Twin debuted in the 1938 comic page Spirou Sportif — Spirou doesn't like water in English. Being a Spirou character, he does not belong to the Walt Disney Company, although Spirou is considered canon on this wiki.
The character has caused much debate in the fandom, over the presumption that he is meant to indeed be Spirou's twin-brother. This is not actually stated by the original comic, which would make more sense if one assumes that "twin" here means "lookalike".