An apprentice magician dinosaur living in Monsterland, Theo Saurus, made a mistake while practising a spell one day.

He turned the lands Jellyland, Pipeland, Spottyland, Cherryland, and Rockland into sad places, void of color or life.

Theo began living in a hidden cave to avoid the wrath of the other monsters until discovered one day by the hero of the story, Mayhem.

Mayhem promised to bring Theo the necessary magic dust to transform Monsterland to its previous happy state.

Mayhem was far lighter in tone than Creatures, which featured end-of-level action puzzles that, if not successfully accomplished, meant death by various gruesome means.