Nandarou
Genres: Comedy
Type: Special, Episodes: 1
Aired: Nov 1, 1992
Studio: Studio Ghibli
Source: Unknown
Rating: PG - Children
Synopsis:
A short TV advertising spot featuring a small green pig with enormous eyes. 

The title Nandarou implies that even its creators didn't really know what kind of creature it was supposed to be. However, NTV (Nihon TV) chose it as their station's mascot. 

(Source: ANN, Nausicaa.net)