The Robot Horse was invented by Murky Dismal for use in the great horse race, part of the Sprite Fair. With all the horses in Rainbow Land were ready to compete, Murky decided to submit his own entry with a secret weapon. The goal of the Robot Horse was to race around the track and spray all the people with a gloom cloud. Once everyone was murked out he would then steal the real horses in the hopes of having them power a fan in the pits that would blow gloom down into Rainbow Land.

The Robot horse, while wobbly in it's construction did succeed in it's task and Starlite and On-yx were captured.