Fliff, a fictional substance, is not legal in Minnesota as it does not exist in reality. Minnesota state laws strictly regulate substances that are legal for use, sale, or possession. It is essential to adhere to the established laws and regulations regarding the legality of substances in each state. If a substance like fliff were to be introduced, it would need to undergo rigorous testing and approval processes to be considered legal. As of now, there is no information or evidence to suggest that fliff is legal or recognized in Minnesota.