Pepe, voiced by Don Messick, was a wicked troublemaking chihuahua in the animated series Foofur (1986-1988), a production of Hanna-Barbera. Foofur himself is a blue hound. The series inspired a Marvel comic book series that ran six issues in 1987/88.
Belgian cartoonist Freddy Monnickendam had earlier done a comic book series for the Belgian market, but it appears not to be true that he created the characters which were already in production in America. There were toys, coloring books, games and other spin-off products.
Foofur Episode Guide