 The character of Caboose (blue armor) was originally not supposed to  be "the stupid one". He was essentially a mere counterpoint to the  Red Team getting their own Rookie Originally designed with only a  hint of smarminess or chauvanisticness, the creators realized that  the fans were commenting more on Cabooses "stupid" comments than  anything else. Caboose is now considered by some to be the most  popular character in the series.