Although not the first Garbage Pail Kid to feature a flag, it is the most original flag created for the Garbage Pail Kid Series - Menaced Dennis #173a of the fifth series. In it, during a scary dream, a bunch of green caterpillars can be seen crawling into Dennis' nose and head. The original flag features a red square background with a brown 'wooden x' fimbrated in white.
The first Garbage Pail Kid card to feature a flag was number #44 Sy Clops in series number two, 1985. The red pennant of a sailing ship in the background can be seen.