Murky is a nasty little being who lives in The Pits, his dark and dreary section of Rainbowland. Just as Rainbow Brite represents Brightness and happiness, Murky Dismal represents glumness and dreariness. Smiles and bright colors send him into fits of frenzy because such things are just too cheerful for words. In his Pits Laboratory, he sneakily concocts vaporous clouds of gloom which can be sent over people's heads whenever he wants to "gloom them down." His chief aim in life is to capture Rainbow Brite's Color Belt in order to disrupt the constructive activities in Rainbowland so that everyone will be as miserable as he is. When Murk Dismal is not plotting mischief at The Pits, he is traveling in his gray and gloomy vehicle, The Grunge Buggy, casting shadows on Rainbowland landscape and polluting the air and all living things with nasty fumes.

From Golden's "Who's Who" Coloring Book